Yamaha MotoGP effort needs a big overhaul, one way or the other. They will not fire Lin Jarvis, he has done well for many years so he is going to be 'promoted' to some other position.
Poncharal left because Yamaha told him that between him and VR46, they preferred VR46 which as a team is all but ready with AGV and Dainese and another important sponsor tied to Rossi, besides Sky and Monster. Look out also for a possible big surprise as Jarvis' replacement: even Suppo's name is being made.
Young talents always keep coming, Mir and Martin and Bagnaia are already in the pipeline and others will emerge. I personally would bet on Mir as the next big thing in MotoGP and believe he'll end up at Yamaha before long.