I think it's an interesting debate. Again, I'm not siding with JG, but when it comes to a successful college coach going to the NFL and being successful, it's not a real long list.
Those that bombed:
Chip Kelly
Greg Schiano
Steve Spurrier
Butch Davis
Bobby Petrino
Mike Riley
Dennis Erickson
Lane Kiffen
And of course Nick Saban
Those that did well:
Jimmy Johnson
Tom Coughlin
Jim Harbaugh
That's it! So, it's not unrealistic to assume Saban wouldn't do any better. One, he already had a shot (Which again, JG hasn't in college). And two, only a small few did well.
That being said, I could make an argument that Saban, because he's such a great college HC, could very well be on the short list. And, if he had 7 seasons with a franchise he could be great. Not unrealistic at all.
But I wouldn't necessarily bet either way because no one knows. I would probably go with the numbers and create the odds.
And I wouldn't call it embarrassing or hilarious to side with either opinion.