More that their planned solution was panned and they didn't have the time to test another one which would require them to rewrite the already satisfactory species.
A damn good thing they didn't go with that too, given the "You can only be one race
really!!!" thing is literally coming up in the US politics in a major way right now (obviously won't discuss further), and it would have been an incredible "bad look" for WotC if they'd managed to bring out a PHB with rules that reflected, however well-meant, that pernicious and bizarre attitude at the same time.
Probably means any future solution will avoid that approach too (thank god imo).
WotC managed to make both player camps unhappy!
Sure, but less unhappy than the UA approach by a long margin, which pleased people who wear tone-deaf and forgetful re: racism (again: c.f.
the news), but totally appalled anyone actually familiar with racism.
Sometimes nothing is better than a bad thing.
Worst case scenario, I think we'll get the "Pick-a-Parent" sidebar in the DMG and nothing else.
If they do that it's going to be a trashfire of an epic scale given what is happening
right now. That would be insane. Completely insane. They'd never live it down. That's a very bad worst case!
Hopefully they've had enough sense to abandon that idea and either just avoid the issue or use extant half-races as an example as you suggest.
It's bad, but it's reversible by, y'know, including them in something in the future. The "pick-a-parent" approach was a huge error that couldn't have been reversed short of a new edition and given its topicality, would have haunted D&D like a spectre for a decade or more.