It's an easy answer, the amount of Valentino Rossi fans worldwide is about the same size as all other MotoGP riders fans combined. If you search a bit you probably find a lot of expressions like “without Valentino Rossi they not have MotoGP”… Dorna (the MotoGP organization and Yamaha knows that… and indirect Valentino Rossi gets money from every racing team… just to not stop...)
People need to understand that MotoGP racing is the most expensive motor sport on the planet, even in Formula One they spent not that amount of money on development of new technology.
In the 2015 season two companies fought for world supremacy, Honda and Yamaha, Yamaha rider Jorge Lorenzo won the world title, but most of the public believe that fellow Spanish rider Marc Marquez had helped Jorge Lorenzo to win the World Championship.
True or not, the controversial win of “Spanish” Jorge Lorenzo (Yamaha) and the involvement of “Spanish” Marc Marquez (Honda) was for both Yamaha and Honda a financial nightmare, for 2016 sportbike advertising and all other advertising for 2016 you probably see more advertising for Yamaha with Valentino Rossi promoting the product… and for Honda you more likely see Honda rider Dani Pedrosa rider in advertising of sportsbike products…
Currently in the advertising business the names of the two Spanish riders from Yamaha and Honda have a bad name… While Dani Pedrosa (Honda) and Valentino Rossi (Yamaha) are still loved by the public… Advertising makes the money to race MotoGP…
Marquez on a HONDA won the race and Pedrosa on a HONDA came third.
No Vested Interest. Marquez on his Repsol Honda won the MotoGP of the Americas.
Lorenzo on his Yamaha came second and Iannone on his Ducati came third.
Rossie fell off.
So who actually WON and came THIRD?
It appears that you guys have a vested interest in Mr Rossi and/or Yamaha Movistar.