Not only that, but the “yearly carousel” was actually years ago. TT was here 2 years (17-18), ARod/Harding had 2 years (15-16, plus they were integral to the staff in 14), Christensen was a disaster for 1 year (14), Johnson/Erickson for 1 year (13), Johnson alone for 1 year (12), Chow for 1 year (11), etc.
Hell, most of the other schools in the PAC-12 have gone through that much turnover or more in the same time frame, with everybody except Stanford having at least 2 different head coaches. USC had 4 HCs and more than that many OCs.