In fact, it's probably true of pretty much every bank every day, since this is partial-reserve banking. If everyone wants their money back, NOW, the bank doesn't have it, but in normal banking, the institutions can be stable for centuries.
SVB put themselves in a somewhat bad situation by heavily concentrating the high levels of deposits in 2019-2021 in long-term treasury bonds (which would not have been permitted had not the previous administration not rolled back Dodd-Frank regulations, in no small part due to the lobbying of SVB's CEO).
So to service the net withdrawals that started earlier this year (lower levels of VC investment and higher expenses in the concentrated startup community SVB served), after the big interest rate increases, they had to start cashing out their T-Bonds at ~80% of face value. This lead to need to raise new capital, which reduced confidence in the bank...
Had everyone, including Thiel, stayed calm instead of Thiel yelling "FIRE!!", it is entirely likely that it could have been at least calmly wound down or sold.
It's kind of like crossing thin ice. If you can keep your weight spread over enough surface area with no mis-steps, you can get across just fine. But if you take one wrong step focusing the pressure at one spot, you are now in the freezing water with a life expectancy of minutes if you are helped.