OK, you've got a point, MTGox is a central point in a supposedly decentralized network. I think that problem has been recognized, however, and is in the process of being remedied.
Good we're on the same page!
But do you realize that the exchanges as a group CANNOT ever be forked from one another?
I'm not sure in what context you're using "forked." Don't we
want all the exchanges (into which group I include the people selling bitcoins for other currencies on #bitcoin-otc, SR, and other darknet sites) all using the same blockchain?