(or, as an argument I made earlier, if your company is completely dependent on a single other company to function, such as AWS, is there really any more risk in having only one bank account?)
> maybe they already do
"Insured cash sweep" (which is basically "RAID for banking")
Cash sweep is insured but only to a limit, there's nothing magical there and the underlying securities have default risk (or breaking the buck).
In 2008/9, The fact that a solidly red administration (Bush) wrote the check and a solidly blue administration (Obama) delivered it on bended knee to the banking industry made it clear who really ran things.
“Paying your bills is a moral hazard” - guy in the background of a tv interview that birthed the tea party in the US.
So in this universe, when you go to get insurance at SVB, you see that it costs you 1% per year, which seems high to you. You go to the insurance company's website, and see that insurance for Chase is only 0.5%, so you switch to them instead. SVB is pressured to change to a less risky strategy by the market, not b the government.
(NB I'm not a libertarian, nor am I recommending this approach; I'm just saying that in theory such a system could work.)
EDIT: Upon reflection, this might just punt the issue down the road: Suppose SVDI (Silicon Valley Deposit Insurance) gives you a rate of 0.1% per year at SVB. Everything is fine until SVB fails, and then it turns out SVDI didn't have enough capital to back their insurance, and you lose anyway.
Maybe there are ways you could fix this, but my preliminary conclusion would be that you need some kind of regulation somewhere.
When the bank fails, they end up living on the streets for their mistakes, and will never (hopefully) be able to do it again to another bank.