To do that you’d have to ban players from ever returning to the league again if they retire. If not you could just game the system by un-retiring a year or two later. We’ve seen Antonio Gates, Marshawn Lynch, and Jason Witten all come out of retirement recently. It’s a fair concept but way to risky IMO.
The Niners went 4-12 last year by virtue of Jimmy Gs torn ACL and got themselves the #2 overall pick.
Lynch did a terrific job with Bosa, Deebo Samuel, Jalen Hurd and Dre Greenlaw all making nice contributions as rookies.
And, as you pointed out some free agent additions on top of what was already a pretty nice rebuild that Lynch had underway.
SF is set up to be really good for a long time....and Lynch deserved to win the Executive of the Year award hands down.