If BitCoins to last with the same dollars flowing in and out of the system... MtGOX or some other large corporate entity will ramp up and make it a single EXCHANGE and then you can open up wallets anywhere that trade on that exchange. Similar to the FOREX that we have now.
Actually there is no one big FOREX exchange. It is a distributed network.
Better to have one big exchange that puts all of its efforts and monies into protecting it and maintaining it and not be worry about every Tom, Dick and Harry complaining about their $100 deposit not going through.
If you mean going to a traditional model where brokers act as gateways to the exchange then you might be on to something. For a long time I thought that model was antiquated -- who needs brokers? just let everyone deal directly with the exchange! I'm starting to wonder whether the old school stock broking industry was as useless as a I thought.