We are saying that players do not just keep progressing IRL. Like I said before if you allow even the non-physical skills to keep progressing just because your player is able to put up numbers then you are going to make a system where HOFers exist but IRL they would never turn out like that.
I know I have bad hands and I dont have the best awareness. But if I have Manning or Brady throwing the ball to me I could probably catch 40-60 passes a year. Under your system, I could develop hands and awareness like Jerry Rice just because I was catching 40-60 passes. How realistic is that?(again if I had the potential to get better hands/awareness IRL I would need a good coach and bust my butt every day to improve my skills) I would then see a probability that I could produce better numbers on the field in the same situation as I did the year before when I had worse stats.