Probably the part of the quote you cut off. The part that made it clear that the development quotes were in regards to developing a Super Bowl winning coach and not just one capable of holding the job:
Last time I checked, neither Kelly nor Garrett had won the big one, yet.
As I said earlier, I like Kelly a lot. And I like Jim Harbaugh a lot, as well. Both of those guys have advance their teams farther than Garrett has, and they both did it quicker. But I don't buy the argument that all teams are equal or that an NFL franchise can be readily turned around in a season or two. It can take more than that. You have to look at the job the guys do under the circumstance they're in, and you have to understand that those situations differ so much that you can't measure the job on short term wins and losses. I've said it several times before, but John Wooden has said that his best job coaching he did for a team with a losing record.
All in all, I think I'd have to say that what Kelly's done I find more impressive than what Jason's done. Mostly because I think he's done it with a snack-pack of below-average QBs and on the strength of his system. But then he's also had a lot of time to work out some of those kinks at the collegiate level, so that's probably too be expected. I like where Dallas is right now, long term, better than where the Eagles are. I think the Eagles are doing a lot with smoke and mirrors and have some way to go yet in terms of personnel. And managing and developing personnel at the NFL level is the hardest part of building a successful organization long-term.