Like you say, Formula 1 is more popular around the world, but there is still a large amount of people that follow MotoGP as well, and I do think that they warrant a game made for them as well, and Ride does that to some extent.
I'd also think that more MotoGP fans would actually go out and buy a game based on that sport than what Formula 1 fans would. There are hundreds of car racing games available, but not many bike racing games so while it is a niche market, there are still a lot of fans of motorcycling that will justify a game developer to carry on making them I would have thought.