Golson can make between now and the beginning of next season. He has a full year of experience in actual Div 1 play, plus a whole year and a half in the football program to learn the playbook, watch film, learn the players. He should have no excuse next fall not to be able to do enough by way of reading defenses and executing plays quickly.
Kelly's ability, to me, is not a question because he has successfully run this type offense in other places with less capable personnel, but with other QBs. The ability at the other positions is not as critical for this to work as it is at QB, so the burden is there.
If Golson can't come out in the first game or two and get this done, I would be for Kelly starting all over training the next guy in line, Kiel, just as he did Golson last year. Golson has had plenty of opportunity and I can't see the team, or Kelly, going through what we went through last year for three more years with Golson at the helm. Time for him to step it up and get 'er done.