Or so I suspect, at least.
We've just seen large investments in US-based bitcoin companies by savvy VC firms. Circle and Coinbase are both saying that they're going to make bitcoin easier for people to acquire and use. I'm sure they'll be successful in that, but they're also probably targeting next-gen uses of the blockchain (see Naval Ravikant, Co-founder/CEO of Angellist's "The Internet of Money":
http://startupboy.com/2013/11/07/bitcoin-the-internet-of-money/ ). Seeing some real apps along those lines will drive another wave of excitement, and convince yet another slice of the populace that bitcoin has merit and is here to stay.
Along the way, someone is going to solve the money-transmission licensing problem. The reason we don't have any solid US-based exchanges is due to state-by-state MTL requirements, and specifically, the surety-bond coverage requirements for businesses to obtain such licenses. Either Coinbase, Circle, or some new well-funded entity will go through the expensive work of getting the licenses, or start a fund/company that's knowledgeable about bitcoin and willing to underwrite the bond coverage. Solving this problem will lead to much better liquidity in the US, and allow for some of the next-gen services outlined above, as well as advanced trading and hedging.
That leads to the beginning of real integration with Wall St. It seems like they're *starting* to shift from completely mocking bitcoin to dipping their toes in the water. They need *much* better liquidity to do anything significant, but unleashing real US exchange platforms will make that possible. Additionally, vehicles like SecondMarket's Bitcoin Investment Trust are already proving popular, and that trend will continue. The potential issue of near/medium term regulatory uncertainty was removed with last month's senate hearings, and further financial integration and products will come as a result, in due time.
In any event, these things are all inter-related and tend to snowball. The hard parts of getting the ball rolling and reducing regulatory uncertainty have already happened.
China can do what they want; I think it's far more likely that the US ends up housing the most robust and sophisticated bitcoin ecosystem.