That's fine - and I'm saying that Marrone is unequivocally a terrible coach. I just think that Tennessee needs to hire a guy who, whether it was at a good or a bad organization, had success as a HC at the P5 level. Marrone might be good, but we don't know, and he hasn't really demonstrated it at any previous stop.
Maybe that's a harsh judgment because he's coached at places, especially Jax, where decisions were made above him that made his job really difficult. But I think it's where Tennessee is as a program. Marrone, whether it was his fault or not, hasn't really proven anything. It isn't like he was good at Syracuse, Buffalo, or Jax for a numbers of years before struggling or being forced out. He was up and down at a G5 program, appeared to be doing well at Buffalo then bolted, then had flash in the pan success at Jax.
If he is thought of as truly a great coach that just happens to have coached at tough places, then I'd expect him to get interest from another NFL team and stay in the NFL.
It's all a crapshoot, really. But the people who make the decisions should and do know more. Freeze is a gamble, too, and some are willing to take that risk. Herman is a gamble based on the rumors of not being able to get along with people and that he didn't work out at a school in a worse league. I don't really see how those guys have "proven" long term success either.
My guess is he will land in the NFL again. Maybe not as a HC right away though.