There is absolutely no reason why MotoGP (even above F1, WorldSBK, ect.) can't be a popular racing sport here in the States. It's a very simple sport: There's a qualifying round to determine starting placement, then when it comes to the race they all line up on the grid, the lights go out, and they race. They don't pit stop, they don't race for 500 stupid miles, it's 20 some laps, 45 minutes of non-stop action with plenty of passing and excitement. Especially if they broadcast the same stream that's on MotoGP.com with the GOOD British commentators who give plenty of information about the riders, the racing, the history, ect.
They just do a HORRIBLE job promoting.