HDTV . . . probably a combination of a few things:
Equipment is very expensive. Even in the NFL CBS does not do all of its games in it due to cost
Size would almost have to be an issue as far as on a motorcycle.
I would think live bcast of it would also be a challenge based on the movement of the source signal and the remoteness of the areas (some). The more bandwidth you have to send, the harder it is

Then there is the part of demand. They would have to make up all these costs with revenue, and that would not happen - at least not the US broadcast of this event. It would not be on Versus if it pulled any significant #.

Lets just be happy it is on and there are so many hours available!!! It could be so much worse, with like a late night wrap up show only.