How would what you are proposing work? Most college football players won't earn much or anything in NIL, so I assume you don't want them to give up their scholarships. How is it decided who is required to give it up, then? As you said above, the $50k these linemen are receiving doesn't even cover their expenses for attending and living at school, so the line must be even higher than $50k. At that point, you are talking about such a small number of students that it would seem ridiculous to worry about it.
Furthermore, why should a person be prohibited from accepting benefits that are legally provided to them in exchange for the recipient doing something legal. If a guy convinces a school to provide education, room, board, food, and swag in exchange for playing football, good for him. If the same guy is also able to get an offer from someone else for NIL, also good for him. I grant you the morals and legalities in the second scenario can get murky pretty quickly, but in no case does it make sense to me to ever take away a players scholarship just because he got some other benefit somewhere else. Should every athlete from a wealthy family have their scholarship revoked?
I can't believe this "ThEy ShOuLd PaY ThEiR oWn Way!!" meme is even treated with any amount of respect. It is impractical, irrational, and, although I can't put my finger on it, I think it speaks to a moral or at least logical flaw in the proponents of the idea.