Interesting breakdown from quora
Why has Donald Trump not yet been impeached?
You want the real answer? It’s because of this person…

Yep, it’s Democratic Speaker of the House Nancy Pelosi.
Now, I know what you’re going to say “Wait a minute! She’s the leader of the Democrats and she more than anyone wants Trump impeached!”
But you’re wrong. Here’s why.
Pelosi is
smart. She didn’t get to where she is by being a timid dummy. Ever since her last stint as Speaker she has been plotting, crafting her return to the third most powerful position in American government. Pelosi’s own party saw her as too divisive to be Speaker after Paul Ryan left the position, yet here she is again. Her own daughter,
Alexandra Pelosi, said “She’ll cut your head off and you won’t even know you’re bleeding.”
Pelosi also knows that it is not in her, or the Democratic Party’s, best interest in impeaching Trump.
At least not right now.
If the Democrats impeached Trump, as many people have tried to get them to do and the Republicans are accusing them of trying to do, Pelosi knows it will backfire on them. Trump is highly popular with those in his base, but not neces
sarily all those within the Republican establishment and Party. But those in his base are loud, vocal, know how to mobilize, and have huge mouthpieces in the form of Fox News and personalities such as Rush Limbaugh and Sean Hannity in their corner. They will play up on the whole “the Democrats have been on this witch hunt for over 2 years” thing and use it as a wedge against the Democrats even if they are right currently or what the Mueller report eventually says.
What Pelosi is doing is letting Trump be Trump. Not a day goes by where he says something that isn’t true, does something that is questionable, or offends someone or something we have accepted as being our norm.
Even if Pelosi decided to let the Democrats proceed with impeachment proceedings right now, which they certainly have enough votes for in the House, there would never be a conviction in the Senate for Trump’s removal as long as there is a Republican majority there.
No, letting Trump be Trump is her strategy. Let him do what he does, and in the meantime gather evidence of abuse of presidential power, corruption, whatever. With this treasure trove of material they will be able to wield it against him where he will be most vulnerable - in the 2020 election.
If, and only if, Trump does something truly, stupendously criminal that meets the standards of Article 2, Section 4 of the Constitution for “
Treason, Bribery, or other high Crimes and Misdemeanors” will they pull the trigger for impeachment. And if they do, which is increasingly possible given recent developments, expect to see moderate Republicans distance themselves from him and vote with the Democrats. Impeachment is an exceedingly difficult thing to do, it’s only been done twice and neither resulted in a conviction.
But once again,
if Pelosi permits it to be used, you can rest assured it will meet the standards as she knows the consequences otherwise.
No, Pelosi will use Trump against himself. And in the event that he is voted out of office, he is no longer shielded from criminal prosecution while being in office, and there will be no shortage of material to use against him.
Edit 2 on 3/11/19: Speaker Nancy Pelosi was interviewed by the Washington Post about this very subject on 3/11/19 and said the following:
“I’m not for impeachment. “This is news. I’m going to give you some news right now because I haven’t said this to any press person before. But since you asked, and I’ve been thinking about this: Impeachment is so divisive to the country that unless there’s something so compelling and overwhelming and bipartisan, I don’t think we should go down that path, because it divides the country. And he’s just not worth it.”
Similarly, in an interview with Politoco, House Judiciary Chairman Jerry Nadler, D-New York said “You don’t want to divide the country, so you have to think you have such a case that once the case is finished being presented, enough people understand you had to do it,”
Sources:
https://www.usnews.com/news/poli...
Pelosi: 'Not worth it' to impeach Trump
Edit 3 on 5/22/19: On Sunday, May 19, 2019 Representative Justin Amash of Michigan became the first Republican member of the House of Representatives to openly call for impeachment of President Trump. In a
report by CNN, Amash said that after completely reading the Mueller report he concluded that “Trump committed "impeachable conduct" and accused Attorney General William Barr of intentionally misleading the public.” Amash sent out a series of 13 Tweets that day laying out the reasoning for his position, further stating that "Contrary to Barr's portrayal, Mueller's report reveals that President Trump engaged in specific actions and a pattern of behavior that meet the threshold for impeachment."
In response to Amash’s statements, President Trump, in the true Trumpian response mode, called Amash “a loser, a total lightweight”.

Justin Amash
✔@justinamash
·
May 20, 2019
Replying to @justinamash
4. They imply “high Crimes and Misdemeanors” requires charges of a statutory crime or misdemeanor.

Justin Amash
✔@justinamash
In fact, “high Crimes and Misdemeanors” is not defined in the Constitution and does not require corresponding statutory charges. The context implies conduct that violates the public trust—and that view is echoed by the Framers of the Constitution and early American scholars.
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Edit 1: There have been a few questions/comments regarding the filling of the Vice President position if the President is removed by Article 2, Section 4. Here is what it says in the 25th Amendment about that:
25th Amendment: Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.
So, if by some chance Trump were to be removed and Mike Pence became President, also not something that Nancy Pelosi and the Democrats want, he would face an uphill battle in getting a Vice President in place as they would have to be confirmed by both the House and the Senate. There is nothing in the Constitution that says there
must be a Vice President in position, only that the President shall
nominateone. In fact, there have been an incredible 18 instances where Presidents have either not had a Vice President or have not filled the position after a vacancy occurred. James Madison was elected President twice, had both Vice Presidents die in office, and both times just left the position open. Why? Becasue until the 25th Amendment was adopted the position couldn’t be filled until after the next post-election inaguration. The last two times this section of the Constitution was invoked both dealt with Richard Nixon, first when he appointed Gerald Ford to replace Spiro Agnew and then when Ford appointed Nelson Rockefeller to be his Vice President after assuming the presidency after Nixon resigned.
If Pence did become President he most likely would have an open Vice President position until the 2024 election was over and the next president was inagurated
Nuther view
Why hasn't Donald Trump been impeached yet?
The Speaker of the House Nancy Pelosi is making a political choice to let Trump continue to embarrass himself and remind his opponents every day what a corrupt and incompetent person he is. The more time he’s in office, the more things he does that can be used against him politically.
If the House were to impeach Trump, it’s hard to see how it would succeed in removing him from office. The Senate Leader Mitch McConnell would work to prevent that. That’s
how the process works: the House impeaches, which is like an indictment, but that doesn’t remove the President. Following impeachment, a trial happens in the Senate, and it’s possible for there to be no conviction. Even if the Senate did convict Trump, they might not remove him from office.
Then Trump would claim this was an exoneration of everything he had been accused of, and all the criticisms against him would have to start over at square one. Politics is not about truth.
Even if by a long-shot Trump were impeached, convicted, and removed from office, what then? Vice President Mike Pence would replace him, and some people believe Pence is even more dangerous, having more political experience (as Governor of Indiana), less political baggage to hinder his agenda, and less obvious mental instability than Trump.
But there’s not nearly as much political opposition built up against Mike Pence’s brand, so he might have a
greater chance of reelection in 2020 than Trump will.
The opposition against Trump is more likely to motivate voter turnout in 2020. He is more likely than practically any another Republican candidate to be defeated. Besides, when more voters go to the polls, it’s usually better for the Democratic candidate in other races. A strong defeat for Trump will make it harder for other GOP politicians, so leaving Trump in office at least through the 2020 election cycle will do more to help Democrats than it would to remove him.
At least that’s the likely reason why Nancy Pelosi isn’t proceeding with impeachment.
It’s unfortunate for all the people Trump is currently hurting and will continue to hurt until he’s out of office, like American farmers, business owners, and consumers (victims of his trade war), and the
50,000+ Central American migrants in detention, and many others.
Nancy Pelosi is counting on the American people to vote Trump out of office in 2020 with enough of a landslide to discredit him and his family and allies.
P.S.: I also agree with
Ray Loewe’s answer