I think you're just plain wrong here. If Harry & Meghan had endured the inevitable sniping, & William got run over by one of those double-decker buses you guys ride, Harry would eventually ascend the throne & their children after him. Maybe as I'm not a Brit I'm missing some rule against that scenario, but on first blush it seems sound.
I'm sorry Meghan had to endure the nonsense thrown her way, & while I don't fault the couple's decision to step away, it compares poorly to other pioneers who broke color barriers in business, government, sports, entertainment, etc..