Drafting a "stud QB" and developing him to a point where you win is a very poor odds proposition. It's not like you just make a decision to go that route and it happens.
IF Baker balls out (3500-4000 yards, 25-30 TDs, and 8-15 Picks) with 8 or more wins, I think it would be very short sighted to not sign him. He won't be cheap, but he will be less than the absolute top QB tier. And I believe he can play top tier enough, coupled with the better roster that comes along with him through cost savings that the panthers could compete for SBs with him.
Those that think Baker is going to go through two "proof it" years are not thinking straight about this. Baker's stock was artificially low for three reasons this off-season: (1) big contract number when teams knew Browns had to let him go after signing DW and 2 backups, (2) combination of the media pile-on and Bakers self-created media spats, created narrative Baker is not a team player and has a bad attitude, (3) playing poorly last year with a significant injury made him look like a scrub.
IF he has the year described above or better, with a good attitude, the narrative becomes: (1) He pulled the Browns out of the dumpster and took them to a playoff win despite inept management and coaching, with a great QB year in 2020, (2) he took a coach on the hot seat and team picked to be in the bottom 25% of the NFL to/on the verge of the playoffs, with a second top 10-15 QB season, (3) he is the reformed, humbled, team player Baker. With that someone is signing him to a fringe tier one contract.