A LOT of regulation goes along with that. These entities eschewed regulation and those investing talked about the benefits of eschewing it.
The people whose withdrawals are suspended are NOT depositors. They’re unsecured creditors, the terms of such services generally say they transfer the right in the tokens to the exchange or lending co.
These companies aren’t banks. They should not have been allowed to grow as they did; they were obvious ponzis. Had they had the regulations you advocate they could never have formed in the first place, or they never would have got capital.