Because someone can point a gun at your head to defeat ECC. They can't do that with banks. That's why people keep their life savings in a bank, and why you'll need a bank even with Bitcoin.
I always felt bitcoin was more about replacing paper money than replacing banks. Banks give you interests, Bitcoin just sits there and the amount (in bitcoins) never changes.
> Because someone can point a gun at your head to defeat ECC.
You can store an encrypted paper wallet in a safety deposit box at the bank if you're worried about that threat. You don't, however, need to hand it over to the bank to lend it out to bad debtors if you don't want to, which is the threat FDIC protects against.
There are at least two problems with this approach. First, this just makes you a target when you go and retrieve your paper wallet. Secondly, even if you never actually leave the bank with your paper wallet, this means you need to physically go to the bank every time you want to transfer money. But people need to transfer money on a daily basis in order to pay bills, meaning any access to a bitcoin wallet needs to be highly available. A paper wallet stored in a vault isn't.
The counterargument to this is to store a portion of your savings in a paper wallet. That's fine, but it's not what's going to make Bitcoin mainstream, which is what the conversation is about. It needs to become consumer-friendly.
I'm merely responding to your argument that people will be unwilling to carry the equivalent of their checking account balance (~$1000?) with them because they'll fear for their physical safety. People carry laptops and credit cards despite the fact it's not any harder to point a gun at me and take me to an ATM in a shady part of town or steal my laptop.
