I think Steley Dan would be F'd without the show. He's been a successful message board stand-up and has greenlit some gays, but the majority of those opportunities turned lucrative AFTER he was a success on the Stern show. Obviously, he made it to TSW on his own, but he also wasn't 320 lbs at that point, and his substance abuse wasn't so well-documented. He had a stretch at the end of TBD radio and the beginning of Sirius where he was absolutely ON FIRE....I had tears in my eyes laughing at some of his bits and especially his off-the-cuff comments about how fat beerball was...Lately, he hasn't been doing it for me...His reality can be funny and entertaining, but for the most part, his "woe is me" attitude makes him sound like a whiney, lazy B word IMO.
On the flip side, there would be an adjustment period, but I'm sure the Stern show would be just fine without Steley Dan. Either rotate sit-in guests in his seat, or hire someone much the same way they hired Steley Dan. Or leave it empty like they do on the one day every week that Steley Dan calls in sick.
Maybe Steley Dan watched "Beer League" during his week off and realized that his career outside of the TSW might not be such a sure-thing.