The best QB's are coming from small schools nowadays, the kids who have less talent around them & have to do all the heavy lifting themselves are the ones rising & becoming top tier QB's in the league.
When you play at a powerhouse program that's loaded with talent all around at OL, RB, WR etc it can mask how good you actually are as a QB because it's much easier to have success, so the small school QB's with natural traits who have dealt with adversity & don't have it as easy actually get better reps & development while in college because they know how to make throws under duress & speed up the mental processing & scanning of the field.
There's a reason why guys like Mahomes, Lamar Jackson, Josh Allen, Carson Wentz, Jared Goff, Daniel Jones, Drew Lock etc are all promising young QB's that have had success early in their careers & are the future of league despite not playing at the traditional powerhouses.
The majority of high ranked 4/5-star QB's in HS fizzle out in college & don't have much success in the league. Deshaun Watson might be the exception to the rule at this stage in his career, but on average, most of the high ranked QB's bust.