Was it lazy giving Thor all that power in IW just to take it away in Endgame?
Answered 13h ago
Not at all. In fact, it’s one of the more fascinating character studies the MCU has engaged in - the notion that a hero’s feeling of self-worth can directly dictate how powerful they actually are.

Thor’s overall story arc in the MCU, from
Thor right on through to
Endgame, is one of constant doubt, self examination, and sudden growth that helps him exceed his starting position.
The plot of the original
Thor movie is writ large across his arc in the MCU in general. Thor is brought low, Thor and/or his friends suffer as he searches himself for his self worth and value, and finally Thor succeeds in becoming the next best version of himself, enabling him to defeat the big bad guy.
It’s no accident that the MCU kept the “worthiness enchantment” as part of Mjolnir when adapting Thor from the comics. (Many people don’t even realize that comic-Thor has a secret identity, an ordinary man with no power whatsoever, and his worthiness is what allows him to turn
into Thor, by holding Mjolnir. Without the hammer, he wasn’t even a handsome, tall, blonde dude.) The fact that his hammer is endowed with this enchantment forces Thor to
constantly be worthy, not only of his own power, but of his birthright as king. As such, he places a
huge amount of his self-worth in his use of it.
In
Ragnarok, he loses Mjolnir but ultimately finds enough of himself that he can defeat Hela (or at least, defeat her forces and hold her off long enough to get the Asgardians away safely on the
Statesman). But that means that at the start of
Infinity War, he’s lost his mobile worthiness-detector.
Think of it this way. He wins in
Ragnarok, and is immediately beset by Thanos’ ship (which we saw in the end credits). This translates directly into the opening of
Infinity War, during which we see him fail to save his brother, fail to save Heimdall, fail to save many Asgardians, and fail to save his ship. The man who only minutes of screen time before was declared King of Asgard gets his ass whupped by Thanos and is left to drift in space until he gets picked up by the Guardians of the Galaxy.
Now, if Thor
had Mjolnir at this point, he’d instantly know whether all these defeats meant he was worthy or not - either he could pick up the hammer, or he couldn’t, and either way, he’d know where he stood.
Instead, he suffers these immense emotional setbacks, and decides that his only way forward is to build himself a better weapon (hence the sidequest to Nedevellir). He succeeds (at great personal risk and peril) in helping create Stormbreaker, crashes into the Battle of Wakanda, and
nearly kills Thanos with a strike powerful enough to plow through the combined power of all six Infinity Stones.
But nearly doesn’t count.
He’s left devastated that, at the last moment, he fails
yet again. Despite all the gains he’s made, despite no longer thinking of himself as “the god of hammers”, despite having tapped into the Odinforce, Thor has missed his shot.
He is utterly undone going into
Endgame.
Oh sure, he’s all fire and brimstone when the Avengers depart for the Garden, and he successfully kills Thanos. But it’s just too late, and it amounts to nothing but an empty revenge killing. He’s accomplished nothing, and he knows it.
So the first part of
Endgame (once it moves forward the five years) shows us the after effect of that. Thor is so tied up in the idea that he may or may not be worthy any longer that he’s become a shadow of his former self. He doesn’t really believe in himself in any meaningful way anymore, and his powers (and physiology) come to reflect it.

Now, it’s key to note here - he hasn’t actually
lost his powers. In theory, he could call down the lightning at any time. He could still punch a rock warrior into orbit. He could leap to the top of any building and then into the sky. But he simply
doesn’t. Instead, he hangs around playing video games with Miek and Korg, effectively becoming a fifteen-hundred-year-old-teenager with no ambition. He’s been defeated in the most devastating way possible, especially for
him- in his own head. He can’t even bear to hear Thanos’ name.
Notice his joy then when, during the time heist, he calls Mjolnir in Asgard,
and it comes to him. Mjolnir
has the enchantment at this point, and it answers his summons. That is literally all Thor needs to become himself again - the external validation that he is, after everything he’s won and lost, still “worthy”. His confidence skyrockets to know he’s still good enough to be an Avenger, and suddenly nothing can hold him back again.
The only worrying part of this, though, is that the validation must be
external. He needs someone else to recognize him and tell him he’s “worthy” (especially now that Mjolnir is lost to him). He fails most of all when he doesn’t see his own worth. He’s amazingly powerful, but he’s also possibly the most fragile of the Avengers, because his crippling self doubt is the only thing that can
really take his power away.
And just like most people, his belief in himself is the only thing that can get him back on track.