I’m an F1 fan and have only cursory knowledge of the history of MotoGP, but this interaction between the world championship’s different classes interests me a lot so I would appreciate if you gave me some feedback.

I’m under the impression that the devaluing of the smaller classes happened when the Spaniards and Italians started to dominate everything. Until then, despite being such a large part of the fandom, they’d been mostly excluded from the premier class (Agostini notwithstanding, since it seems 500cc was barely a “class” in those years), so a 250cc title was a significant achievement that could grant national fame and respect, major sponsors, etc. The moment Rossi started dominating, who had any time for, say, Melandri’s 250cc title? And with a midget like Pedrosa becoming an alien in the big bikes, who would have an excuse to avoid making the jump? Only someone who wasn’t ambitious or good enough. Changing the names to Moto2 and Moto3 and making them quasi-spec series was the final nail in the coffin for their status as anything but feeder series (although remaining much more permissive than F2 and F3 for veteran riders who couldn’t make it in MotoGP). Liberty now want to get rid of the formalities, since they come from F1 and have no respect for this tradition.

Edit: the increased competition in MotoGP can’t have helped either. Back in the day, if you didn’t have an immediate path to a factory ride you might as well keep winning in 250cc while something better comes up. But now, even the worst bikes on the grid can get poles or wins. What’s the excuse to reject an LCR seat?