Yes, I understand that now. I was under the impression that the coin limit was somehow fixed forever and could not be altered (like a transaction deep in the blockchain can't be changed anymore). But that's obviously not the case.
Great idea
Some basic rule can be fixed into genesis block, and each new client version must follow these rules. Unfortunately Satoshi did not make this happen, or it's already hidden in the genesis block? Maybe a hash of some string there is just 21M
