People don't quit a union station in this day and age. They get fired. No one wants to give up the benefits that come with the job, like health insurance. Yeah, they'll have it through AFTRA for a while, but not that long. It's more likely that they didn't fit in with Jhani Kaye's plan. KTWV is very much a work in progress, so I expect many more changes in the coming months.
As for morning drive, there were others before Dave Koz. Paul Crosswhite as well as Keri Tombazian and Sheryl Bernstein, billed as "two chicks with an opinion". Once they went to Dave Koz and Brian McKnight the Wave ceased to be a "Live" & local morning show.