I had heard from alot of guys who had worked with the new Freestyle league, that skateboarding and freestyle BMX were trying to exist outside of USAC rules, in other words, go in under a "action sports" league, outside of cycling and the UCI. I had heard that that was one of the major sticking points... USOC wants them, badly, They want in, UCI wants to regulate it (hence the "hey they are ALL wheels thing), but Gary and others were sticking to their guns about NOT being under cycling's heel, and basically saying, hey, you need us, not we need you.
so maybe things have changed, I had heard this last year. If it does happen without the UCI, then they wouldn't be taking the spot of any Cycling disciplines, but might be kicking out some OLD sports.
Regardless... I really don't think BMX racing has much to worry about. If you really look at it, it's pretty awesomely entertaining, that SX stuff. It really looks like motocross, and exciting. And that's the point of getting this type of stuff into the Olumpics.