The sad thing was that CoD Mobile was the last decent game in the series. Just think about that for a moment: a freaking cell phone game is better than any CoD title to come out on actual gaming systems in practically a decade.
I agree that it's probably mostly children / teens that play those games, but I'm sure a non-insignificant portion of their player base is the type of person who is A-OK with listening to nothing but pop music.
Nothing inherently wrong with that, but they are either afraid of trying something new or they aren't interested in discovering what they may end up enjoying more than the same derivative time-wasters.