From everything he's been saying, this was a personal decision and I don't have any reason to believe he's lying. He's said on the air numerous times that it came down to the fact he's not getting any younger, and that he has lost 5 or so friends over the past 12 months. He wanted to go out on his own terms. Yes, he didn't like how the business of radio had changed, but it sounds like ultimately this was his personal choice, especially when you take into account the fact Entercom/Audacy management have left the door for him to come back. Either way, a well-deserved retirement for Kane-O.
In terms of replacement, I'm glad to hear Audacy is sticking with local talent. According to Dave, Marti Casper formally of WLGZ will be taking the role at least in the interim. I didn't have much faith being that afternoons are being VT'd by Dan Hardee of KQMT Denver.