Riley Leonard isn't going to be drafted, and unless he can show that he can complete a downfield pass with regularity, he'll be lucky to be offered even a free agent contract (and not a priority one).
I can't quite remember the fellow who claimed that Riley Leonard would be a 1st round pick last year...
In the end, it's not surprising that the guys who had the longest careers were dropback passers who would simply get rid of the ball instead of taking a risk running it. Joe Montana, Warren Moon, Tom Brady, et al., wouldn't have lasted nearly as long had they taken off scrambling on a regular basis.