I don't know that they "screwed" around with substandard coaching... You take a shot on these coaches and sometimes it doesn't work. Dooley failed and Kiffin was a disloyal jerk... Neither are unique in college football- Weis, Nutt, Petrino, Neuheisel, RichRod, etc. You never know whether something will work until you try it.
Before you start... Neither Miles or Saban had impressive resumes when they arrived at LSU. Richt nor Muschamp had ever been a HC. Freeze, Sumlin, Meyer, Sweater Vest, Franklin, etc came from mid-majors or lower. Few "big splash" coaches exist and even then they fail as often as they succeed.
BUUUUUUTTTTT... your major point is dead on. Jones has a better roster in '13 than he will have in '14 and likely better than '15 due to youth. He needs to establish his coaching ability THIS YEAR. Too many are writing off this fall without realizing how critical it is to the future of Jones and the UT program's near and mid term success.
I do not believe he's UT's HC in 3 years if he does not manage at least an 8-5 record this fall. Maybe wrong... but I am willing to be on record.... and I make very few ironclad predictions.
I have little doubt at all that 8 wins is what it takes to show these recruits that he's moving UT in the right direction. That or better and he can sell his ability to coach plus early PT... that's a powerful combo.