Schultz, who is still fairly universally beloved (including by Watterson I think?) went on forever. So did Johnny Hart (BC). The trick is that they're not really trying to get a laugh out of you every day. They're a slightly surreal setting with warmth, and a few recurring gags.
Larson and Watterson were high intensity in a way classic cartoonists weren't. That's not bad, but most people are probably going to burn out or worse (e.g. ending up like Scott Adams).
I take Schultz as the epitome of the “danger” of going forever - the early Peanuts is substantially different than the later ones.
But he’s also a good example of “growing with his audience” - the latter strips pleased his readers even if they didn’t gain many additional.
I do find that it’s sad that in an era of increasingly cheaper and cheaper printing that comics continue to shrink.