"those that can get the political connections" ... if you have the capital and do the paperwork and follow the regs, you can start a bank and get access to the discount window.

"insurance fund couldn't handle yada yada yada" ... the FDIC is implicitly backed by the full faith and credit of the US government. As long as the Treasury exists and has the ability to tax and borrow, your deposit is money good up to FDIC limits.

if you're going to invent new money, makes sense to understand the existing money, and try not to invent something worse.