I allow flying races but I insist they have in their background story a reason why they can’t fly right now, and I’ll bring it into the story and play later on so the character can do something to regain their flight when they get to the level I’ve decided they can have flight in this campaign (usually 8-11)
It cannot - more and more content is coming from AI so they are just “relearning” what one of the AI platforms has already produced… the endgame of that is convergence on nothing new being produced from AI