You don't see the difference between institutional investors losing ill-advised investments, and small businesses not being able to pay salaries? This letter asks for the feds to help depositors, not investors.

This is exactly the same issue FDIC was meant to prevent, though most of SVB's funds weren't protected by it. FDIC isn't a capitalist fever dream: it's excellent regulation that helps protect the little guy, while the bank can be allowed to fail. Great policy.

What you're advocating for is the capitalist fever dream, since it pretends externalities don't exist. Letting depositors fail to spite 'big banks' is the most ill-advised crap I ever heard.