To start as Rookie and therefore will be most likely to have long successful careers. The real question is if it would be worse or better for them if they would have sat a year.
Aaron Rodgers, Mahomes, Montana, Young. All started Later on in their careers after watching. Do we know if they would have been better off starting as a Rookie. No we don’t. Do we know that those who started as rookies would have been better off sitting a year, no we do not.
The problem with the analysis above is you are comparing QBs with different talent levels