Even if a bank chooses to use their own ripple, given its so fast, they just need enough for their volume of transactions for the temporary period it takes to send the funds, like every fifteen minutes.
Still find it hard to believe that will be hundreds of billions
I don't believe Ripples long term goal is just financial institutions. Based on recent statements, they will attempt to work with commercial businesses.
I also believe they will move to P2P as well. I think one of the reasons P2P was not their goal in the past was based on legal restrictions that should be resolved in March of 2018 or 2019 ( can't remember exact details).
Even with that you could still be right, however, speculators don't care about the reality so who knows how the price will grow. Most of the crypto market is in Alpha or beta and look at how overpriced they are.
Three weeks everyone knew XRP would never move out of the .20 range and they were all proved wrong. If I'm not mistaken, the average thought process here was it wouldn't hit a dollar for 2-5 years and some sold their positions.