USC is looking for a homerun hire that brings a big name and gets the fanbase excited. The other big thing will be an ability to recruit at very high levels, since this has dropped off recently under Helton (frankly, not sure that's Helton's fault so much as the ongoing uncertainty regarding his future. Hard to commit to a coach who could be gone at any moment).

Kalani has done great, but doesn't have the biggest name and has gotten by with subpar recruits (per recruit rating services), so he won't be a USC candidate. Neither will Whitt (Whitt might actually get a cursory look, but he'll never really be considered).

James Franklin, Chris Peterson, Urban Meyer, Bob Stoops all have the name value

If you're looking for for a guy with less name recognition but solid results, there's a few others who have stronger resumes.
Fickell has experience at a top-level program (Fickell was on staff at Ohio St, Sitake's highest was Utah), has more completely turned the program around (11 wins in only his 2nd season, just finished his 3rd consecutive ranked season; Kalani went 4-9, 7-6, 7-6 before getting his first ranked season last year) and has connections to the AD at USC.

Even Matt Campbell would likely be preferred, given that he's reached the same heights as Kalani, but has P5 experience (which matters to a fanbase) and has done it at 2 places (Toledo, then Iowa St) so is more likely to be legit.

To clarify, I'm not saying Kalani isn't legit or that they shouldn't consider hiring him. He's absolutely be a better choice than several of the names listed above (...Bob Stoops most obviously). But given what USC wants, I just don't see it happening. Which is great news for us.