I'd guess there are more racing type bikes and parts in the US than anywhere else in the world, even Europe, because we had the money and the market for them. Especially 70s stuff.
Ted, still in Berkeley, where you can't help but trip over Cinellis everywhere you go.
(Just kidding, but a beat 60s one turned up with a baby seat and one of those kiddie 1/2 bikes on the back at my son's soccer game a few weeks ago. Unfortunately, the owner knew what he had; I asked)