Players have been enrolling early for no short of 20 years at this point LONG before NIL ever became a thing.
Some kids would prefer to get a head start on college.
Heck my niece is a senior in HS now and for spring classes at her high school has 3 classes. She leaves the HS campus at 11 am everyday and goes over to the CC which is partnered with the school and is earning college credits.
Kids enroll early ALL THE TIME. It’s not even an exclusive thing for athletes.
As for ‘finishing out your senior year’- take a look at current reports on schools, fights are at an all time high, teachers are leaving in droves, and schools are now being run by whoever has the loudest parent… can you really blame a kid for saying ‘screw that’? Particularly when that student would still be invited back for sponsored school functions like Prom and graduation?