"Uninsured" doesn't mean "all of your money is gone, sucks to be you", it means "you'll take a haircut proportional to the amount of missing assets from the pool." And yes, if the bank is a Ponzi scheme, then that pool is empty, but SVB's problem is liquidity, not overall solvency. The money is there, it's just locked at a suboptimal interest rate, which may cost you 10 - 20%.

This isn't like FTX where your "assets" are worthless IOUs written to yourself.