If you check the history of banks and a specially modern banks, you know its all designed for this. Since the legalization of fractional reserve (which until the 19th century was illegal), institutions were made to give the ponzi scheme better footing.

If the scheme fails in your branch, because people learned about it, a higher institution should exist where they can ask loans to keep the scheme going on. The Central Bank is meant to aid those banks, so in theory a bankrun should not affect a whole country. But said Central Bank also practices fractional reserve so, those guys formed the IMF and World Bank just in case with the capacity to aid those central banks.

It was never about deposits. People should be aware of the danger of giving money to a bank, it is a loan, they only promise to pay it back when you want to withdraw.

Just like any other scheme, when the people learn the truth and want out, it collapses. Imagine if your usual multi-level ponzi schemer had State backing, that's what banks are.

The idea that a bank would just custody your money (for a fee), was pretty much abolished more than a century ago. Now they even pay you because they need the reserve which brings them a potential 10x increase in phantom money, aka credit expansion etc.

Whats worse? Yes, exchanges are doing this as well... And "stable" tokens. Ponzi backed on ponzi backed on ponzi.