The context is missing though. For instance, his first year at Ark was a step backward from before he came. Had nowhere to go but up. As was his first year at UGA, a step backward. Nowhere to go but up. Then he was handed the keys to the #4 talented team in the nation. Of course numbers went up. Now, with tons of more talent he's nearing Richt's best offense of 2014 (41 ppg), but didn't reach it.
You can see the UT offense went down the first few years. Not progress. A great 2012 with veterans was a 1-off, but had he stuck in 2013 the numbers clearly would have went down again as all our talent left (not his fault).
The issue is he really doesn't have a system that can get through times of less talent. He needs constant talent or else he struggles.