There are some who believe he was given a raw deal at Texas (not enough time, no support from his AD, etc) and that if he goes back to Florida where he's better connected to the recruiting world he could really kill it in recruiting.
Then of course there's just the recycled coach factor, more prevalent in the NFL, but they are often still considered safer bets.
So at some point he'll likely be given another chance at a major university. Even though his personality seems a better fit for a mid-major school, maybe he learned from his time here the need to be more than just a football coach. He just really struggled trying to manage the team, recruiting, and all the political mess that comes with the job.
Plus, he's a really good guy that deserves another chance somewhere. He wasn't ready yet for a job like Texas, buy maybe he'll be ready next time.