Although technically you're correct, but most people don't think Bitcoin is the safest asset and they not have enough knowledge to hold their coins to be secure than hand to centralized entities.
I am also a little confused by what the OP said, because as you said that there will be insurance that can be responsible for returning or helping our money to return. And in the process it seems so easy for the Bank to go bankrupt, I mean before that actually happens, customers will start withdrawing their money before bankruptcy actually occurs.
Also here there will definitely be a role for the government, because after all this is in the country and there will definitely be certain regulations that can protect its customers.
indeed by investing in bitcoin, we will not experience this kind of thing, unless we are not careful in storing bitcoins.
It depends on what the reason the banks to go bankrupt, but when there's something bad happen, I'm sure the banks will halt all withdrawals, leaving no one able to withdraw their money.
You're correct the banks are insured, but not all banks are insured, in this case you need to check the banks in your local.