As an aside, I feel that the U.S. has basically saved Bitcoin with this ruling. I've long relied on the world's governments to 'save' Bitcoin by making it illegal, but this is even better. Bitcoin would change to something quite different if it had to support the load of a large exchange economy. If it remains a vehicle for speculation (which happens off-chain) and moving relatively large blocks of value around, it could remain similar to it's original implementation in terms of being peer-2-peer.
I had a strong feeling this is exactly what you would say (I've just been waiting for you to say it), and I tend to agree with you. I keep saying that Bitcoin isn't well suited for daily purchases, but fantastic for other things (primarily an asset/store of value that gives me total control).
the only reason bitcoin is a store of value is because people anticipate it will be useable for daily purchases.