I’m thinking it’s more about how much of the abuse you can tolerate. It’s not like the US has been all that hesitant to abuse our allies in the past. It’s more like our allies have previously been able to convince themselves that the benefits outweighed the costs.

I think you’re right. The world has accepted, or at least tolerated US hegemonic dominance because it worked well enough, but that doesn’t mean it was ideal. Far from it, for many countries. It’s not like the world was given a choice, really. Or, more accurately, the world’s choices were severely limited. Perhaps a majority of the world’s countries just saw US hegemony as the least bad option. But even those countries that didn’t agree that it was the least bad option, what were they supposed to do about it?