Even if we have a cascading failure, the FDIC coverage backstops at $250,000, and it only recovers depositors, and we are talking about loans here, not deposits.
If banks fail, they fail. It may short term feel very painful for people, that I can agree with. My point is, as both a society and as a market place, need to eat the fruits of which grew from what we have sewn. If that means a lot of people get hurt, maybe finally we'll learn a lesson this time that allowing banks to act with impunity is a terrible idea and distorts the overall marketplace.
Ending those distortions will net win when the dust settles, allowing new players and new ideas to grow.
Keeping depositors whole isn't the same thing as backstopping terrible loans or other bad financial activity. They used to be largely separate entities until the "reforms" of the 1980s and 1990s. Perhaps there is something to be said for separation of concerns here