Earlier quoted context omitted.
I might be mistaken, but are not several "traditional" banks offering crypto wallets for customers? Is there a realistic chance this kind of bank is going to steal their customers' crypto and going (at least, next to criminal investigations) bankrupt over it?
Sure, they could. Would that be any different from how a bank could steal funds from a traditional deposit account? By making a bank the custodian of your crypto wallet, you're placing your trust in them and should have similar legal recourse you would have had with a fiat deposit.
As far as I know all the cases of stolen crypto have been newly founded companies with their only business being your crypto. That is quite unlike the other kind of bank.