I read somewhere that is when Bill Waters (of Calvin & Hobbs) quit creating, when syndication was his only viable option moving forward. (I think he was burning out)
I loved Garfield as a kid, but as an adult it was really dull. I tried to even enjoy the old stuff... But this makes Garfield awesome again: (you may need some Garfield experience before appreciating this)
I may be off on this a little, as I did a little reading to verify. Waterson was opposed to having other people write and draw the Calvin & Hobbs cartoon for him. He noted that so many other cartoons had done this and their quality had plumetted.
From memory (because it was written in his last book, and I can't find it online) he said that when he couldn't make a new cartoon every day and be happy with the quality, he would be done.
Edit: I may be conflating syndication with licensing.... :P
Unrelated but I'd like to plug this which is brilliant, though it seems the author burned out a while ago. One of the best comics I've come across https://abstrusegoose.com/
Hit Random a few times and you'll start getting some good ones. He seems to be a high level physicist so there are some impenetrable bits of maths etc. which you can safely skip.
Gary Larson (Far Side) [0] is a great example of a great cartoonist who quit while he was ahead. I was both sad and appreciative when he stopped. Fawlty Towers [1] is an example of a series whose creators also intentionally stopped it before it jumped the shark.