Univ of SoCal's new AD was also AD at San Diego State and Colorado before Cincinnati. He actually hired Jeff [name redacted] at Colorado before Wellman fell in love with him. The pasttwo AD's were Pat Haden and Lynn Swann and things have been on a downward trend with the hiring of football coaches.
Helton Had a good run with Sam Darnold, but that's about it. Aside from that, the best thing you can say about his tenure is that he isn't Lane Kiffin or Steve Sarkisian. Conversely, he's not Ed Orgeron either. I think it will be a miracle if Helton survives past next year. Recruiting is in the toilet and they open with Alabama next year. They also have ND, Oregon, Utah, and Washington, but all of those PAC12 teams might take a step back with new quarterbacks starting.
All that said, I would be shocked if they come after Dave Clawson unless he goes 11-1 next season, which he won't. Also, Clawson's not leaving Wake for the restaurant scene in LA. I agree that you're right that he may leave if he feels like he's accomplished about as much as he can here, but it's going to be hard to make a jump to a "bigtime" football school without putting together a couple of miraculous seasons.