A writer has to fill column inches, and you could do worse for readership than speculate about the resurgence of a power. I just don't think Lincoln Riley built much at OU. I think he sort of stood over the Stoops era (a different era both in coaching and football landscape) and watched it erode. I'll be surprised if this is what USC is really looking for long term.
Venables could work out. There's no reason to say he won't, other than sheer blind odds that any new coach gets. I'm just thinking he's got a lot of headwind next season.
I agree with your assessment of Riley at OU. When he came in as the OC, he helped revive recruiting, and that was good. And he got creative with the offense, and that was good. But as HFC, he didn't maintain the program that he inherited. I think OC is the position he's best suited for.
I don't think he'll do as much for USC as the USC fans think/hope that he will. I suspect that he sees USC as his stepping-stone to the NFL.
OU's head coaching history is perhaps not the norm for a P5 program in that the most successful ones have not previously been head coaches. In 1946, Jim Tatum, who had been an assistant to Don Faurot at Iowa Pre-Flight during WWII, was hired on the condition that he bring in as his assistant Bud Wilkinson, who had also coached under Faurot at Iowa Pre-Flight. Tatum got the program headed in the right direction with an 8-3 season, including a win in the Gator Bowl. But Tatum quarreled with the AD over control of the
recruiting slush fund, and left for Maryland. Wilkinson was elevated to head coach and had a great 17-year run. When he left after the '63 season, his assistant Gomer Jones was elevated to head coach and failed, 6-4-1 and 3-7. In 1966, Arkansas assistant Jim McKenzie was hired, bringing fellow Arkansas assistants Chuck Fairbanks and Barry Switzer with him, and got things back on the right track at 6-4 (in the process, ending Texas' 8-game winning streak in Dallas), then died of a heart attack. Fairbanks became the head coach and had a good 6-year run, finishing with 11-1 seasons in 1971 and '72. Switzer then became head coach and had a great 18-year run. His assistant Gary Gibbs took over, had five decent years, then a crappy one, and got fired. Howard Schnellenberger, successful head coach, had a mediocre 5-5-1 season, and alienated the administration and fan base in the process, so he was fired. Former assistant John Blake was hired and was a miserable failure, producing the worst 3-year stretch in program history. Then came Bob Stoops, never a head coach, and had a great 18-year run. He brought in Lincoln Riley, who had a very good (albeit declining) 5-year run.
So, starting with Tatum, OU has hired eight never-been-HFC guys as HFC, and five of them have been successful. Three of them--Wilkinson, Switzer, and Stoops--are in the CFB HoF. It doesn't prove that Brent Venables will be successful, and maybe he won't be. But it might explain why OU has been willing to go that route much more often than it has searched for a man who has previously been a successful head coach.
P.S. I see that Jim Tatum is also in the CFB HoF. Also, in his one year at OU, he brought in several guys who would go on to successful head-coaching careers. The most notable of them was Darrell Royal.