Those annual 5-year extensions?
My guess is that PremSuck had annual options
Or contractual buy-outs for both parties. If he is leaving, I suspect it's a retirement for medical/health reaons. I haven't listened to him in nearly a year, but even then he sounded like was struggling to breath the longer he talked. Besides, he's no spring chicken, he's probably in his late 70s. The man may be just worn out.
Over the years, I've found the guy as exasperating as most here have, but to be fair, he deserves to be recognized for what he did do. First and foremost, he was there, no prima donna/drama stuff like with Bell. And I do respect him for insisting they do live shows on holidays. There are a lot of lonely people who appreciate that. I honestly believe he cares about his listeners, something Bell never did.
I also don't think a lot of people realize how difficult it is to replace a legend. Back in the day, that was referred to as the "Gene Bartow Syndrome," named after the guy who replaced UCLA basketball coach John Wooden. All he did was win 10 NCAA championships, including 7 in a row. Bartow was a good coach, he won something less than 700 games in 36 years....but he wasn't Wooden. Despite going 52-9 in two seasons, he was never accepted by UCLA fans and left to start the basketball program and run the athletic program at UAB. Nobody replacing Bell was going to placate his listeners.