If you have that much money, FDIC is not adequate for you (and isn't intended to be). There are other mechanisms for those sorts of depositors. Surely, those businesses got solid financial advice and are using them, right?
So, let's say you are a company with 4 banks accounts. Each has $500k in it. One of them is SVB. You probably just move the $500k into one of the other bank accounts. It's no big deal per se, but you do it. That's a run on the bank if lots of companies do the same thing.
This is a chicken and egg situation.
JPM has assets of ~15% of GDP and has 66 million household clients.
I'll take the odds that it's too big to fail.
There are better options than playing these odds. Spread across banks, hold short term treasuries etc. Treasury functions at a company exist for a reason.