I think Artie would be F'd without the show. He's been a successful stand-up and has greenlit some movies, but the majority of those opportunities turned lucrative AFTER he was a success on the Stern show. Obviously, he made it to MadTV 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 FM 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...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 Artie. Either rotate sit-in guests in his seat, or hire someone much the same way they hired Artie. Or leave it empty like they do on the one day every week that Artie calls in sick.
Maybe Artie watched "Beer League" during his week off and realized that his career outside of the show might not be such a sure-thing.