Who said I wouldn't let the Jets make adjustments to their roster? What I said was that either way it's a multi-year rebuilding plan where you would need to rework the bottom half of the roster. If you go with the Jets roster you probably have about a dozen players that might be worth a 1-3 round draft pick. The rest may be NFL players, but they are marginal ones that are pretty easily replaced and would probably be gone by the end of any 4 year plan (the NFL is brutal that way). Alabama generates 5-10 day one or two picks (meaning roughly 25-30 on the roster) and 8-12 total picks (30-40 on roster) each year. Since many of those players would not be NFL ready year one, you'd have to bring in 25 or so replacement level players for the first season and the team would be terrible (top 1 or 2 pick), but each season a new group would mature and by the end of year 4 they'd be a potential contender. The roster starting with the Jets would also add new draft picks every year but wouldn't have the added benefit of having the equivalent of a second entire set of draft picks maturing each season for 4 years. That formula hasn't worked for all but a handful of the last 50 years.
That's a lot of words to talk yourself into taking a college roster as a base for an NFL team over an NFL roster.
I will make my POV simple. Jets players 13-53 may be marginal NFL Players, but they are presently NFL Players, with the experience and athletic maturity to be there. If they were to be replaced, they would be replaced with other NFL ready players.
Players 13-85 on the Alabama roster are not NFL ready. If they were, every draft eligible body, redshirt sophomore and older, would be on an NFL roster come Labor Day, drafted or not.
This is not to say that the Alabama underclassmen don't have potential, but current NFL players are fulfilling or have already fulfilled that potential.
At the end of the day:
NFL player (Even on the Jets) = Alabama + potential.