There are several problems with that idea.
First you have to define what it means to "retire early"
Next you have to come up with a system that determines what compensation a team will receive based upon the player.
Than you have to address the possibility that this could be gamed by having say an injured player "retire early" to get the comp pick only for him to announce his re-entry to the NFL the very next year.
Honestly the only thing I could see doing is maybe providing compensation for a player who while healthy retires from football during his rookie contract based on where he was selected and how many years he actually played. Even then it's dicey.
I think with all the complexities it doesn't make much sense overall. The psychology of the player, the likely-hood that he might retire early is just going to have to be something that team's scout for. One of the things that was never mentioned as a weakness with Luck I think was his varied interests. I've said before that I had a feeling that he might retire a little early because of those things, I just thought early was more like 35 and not 30.
Just means that you are going to have to do your homework on your player and a player who seems like a person that might have dreams other than football would have to go as a negative on their draft profile as someone who might give it all up early to pursue other things.
I remember Deebo Samuel putting on a clinic at the Senior Bowl last year and so wanted him for us in Round 2, with our early Jets pick.
Everyone has got a plan till they get punched in the mouth. When the pads come on and contact is allowed within 5 yards, we will see how well the WRs separate. Deebo's translated to the NFL and the 49ers are reaping the rewards.