I'm pretty sure people will like the grille enough it will be a non-issue for them. Even people on here will eventually get used to it.
When the GT-R first came out, I was a Nissan owner and thought "no way in hell people will want a car with grille that looks like a college athlete in the middle of spitting out his mouth guard"
But then people lost their shit over that car (in 2008.) I thought "Surely someone will come along and fix this!"
But you have to search pretty hard to even find an example of a bumper that fixes the problem. Abflug seems to be the only ones, offering a couple of options.
But i've never seen a car IRL equipped with one of these "grille fixes." I think it's just not worth the trouble to most people. I suspect the same will be true for the new M cars. Old school enthusiasts won't love it, but they'll get used to it and it wont be worth the money to switch. In the meantime, a bunch of new buyers will be like "that looks tough as hell" and buy the car because of the ugly grille.