Like I said before, states are by far unable to guarantee, let alone replace the whole banking system.
Perhaps you haven't been paying attention, but the guaranteeing part is exactly what just happened in the US.
As for the rest - where's your evidence that states can't replace the banking system? States can certainly buy and run banks, and historically they've usually done this with greater success than the bankers have.
Your position seems to be based on nothing more solid than wishful thinking, repetition and ideology.
It's certainly not based on history or fact.
States can buy and run banks, better or worse. The example of Credit Lyonnais comes to mind here.
My position is that the state is not some all-powerful monster. I don't say it's not competent, although even that can be discussed, but that it isn't big enough. Free at last! Free at last! Thank God Almighty, we are free at last! (Martin Luther King)
the state is not some all-powerful monster