Well, ultimately, you get a choice in what you can grade and so does anybody else. If they send in 100 1989 Donruss cards -- or even 100 new Ja Morants -- and lose their butts with mediocre grades because they submit anything they probably won't do it again.
I grade oddball and weird stuff that I like -- and many might scoff at -- but I paid my $X to do so just like the guy sending in 50 Luis Robert cards. CSG is offering the service -- and they're being a lot more democratic (like ground balls in Bull Durham) without prices that are three-figures to get a card graded. Without that, a lot more people won't be grading and/or buying graded cards right now.