So by decentrilization you mean different banks issuing money. I guess we are still in a decentralized economy then since different nations / organizations / banks are still issuing money. Guess what. No.
You could "issue" your own IOUs which would constitute your own "decentralized" currency. As I have earlier said in one of my posts somewhere around here, in medieval times you could bring an ingot of gold to the mint and have official coins minted from it, so there is nothing new in "decentralization", which you apparently promote as one of the virtues of Bitcoin...
In any case, decentralization will be of little, if any, help for Bitcoin. Gold was "decentralized" too, so no difference here...