There are still many folks that aren't aware of the reason Bridgestone left MotoGp.
Contract, money etc.. was never a contributing factor as it's been introduced.
Quick quote before a link that goes into a detailed interview with Hiroshi Yamada, manager with Bridgestone Global Motorsport Department.
"In MotoGP the Bridgestone tires are provided for free to all competitors. Has this expense been a large influence on Bridgestone's decision to leave the MotoGP series at the end of this season?"
The reason we have decided to leave MotoGP after fourteen seasons is simply down to the fact that we achieved all the goals we set out for ourselves when we started the project in 2001. As well as increased awareness of our brand, through winning many races and consecutive world championships in the tire competition era, and then becoming the first sole tire supplier to the series, we established ourselves as the technical leader in motorcycle tire development.