Meh, IMO, that's a little too loud. Marines were made for shipboard discipline (think MPs in the Army) and to help with ground landings. They were very un-seaman-like. Due partly to that and partly to the fact that, like security guards everywhere, the bigger the better, they kept hitting their heads on the hatches, and thereby obtained their nickname... Jarheads. We'll leave inquiries about normalized mean IQ to those more qualified. But, no... the Marines would still be the Marines without airplanes. Marines, like every other organization, are highly susceptible to tribalism and mission creep and its attendant budgetary advantages. Whether we need 'em or not, planes cost a lot, and WE need to fly them. That means more budget. That means more influence. That means more spending...and more budget... and more influence... and more spending... ... repeat ad absurdia.
The Osprey is a fool's errand ... and the US taxpayer is the last fool standing.
Just for the record, that said, I know a bunch of Marine aviators who are some of the finest aviators out there. I also know some who... well, yeah, not so much. Kinda like life in general. Damned near everything conforms to the 80/20 rule.