No radio ratings expert but it seemed 92.9 enjoyed their best days as "cool oldies", I believe that format had the longest run. That Tucson doesn't have a true oldies station will forever irritate and puzzle the heck out of me. There must be money to be made, still, with that format.
KLPX, KRDX, "The Groove" (whatever their official calls are now), KHIT on FM. Oh, and KMXZ on weekends.
KCEE, KGVY, and KTUC on AM. (Yes, I know that 'GVY has an FM now, but it really doesn't cover Tucson, just south of town.)
What do they all have in common?
On not one of them will you ever hear any current music.
How much "oldies" coverage does a market need?
If there is a gap to be filled in the genre, it would be for a "newer oldies" station to focus mainly on the years from the late '80s through the early '00s. That's all that's really missing.