Is there really more parity? That particular talking point picked up a lot of steam during the CFB season this year, but I think it was a reactionary take on the back of a few unexpected upsets.
What was true before NIL remains true today--the only teams capable of winning a championship in football are the blue bloods. Now, power has balanced out much more nationally across said blue bloods as the "pay gap" between the SEC and other conferences was eliminated, but I wouldn't exactly call that parity. It's still the same teams at the top.
What has definitely changed through NIL, and perhaps more importantly the transfer portal, is the speed with which a good coach and organized booster base can turn around a struggling program. See: Indiana, Colorado.