I think he's a product of his time (pre-internet). He stopped because he felt he hit the limits of what he could create, and while a large part of it was the restrictions the newspapers put on him, it was also that he was running out of ideas. It's something he's specifically said in his very rare interviews, and he seems to enjoy living a very quiet life.

While webcomics are thriving, they don't quite have the same cultural impact that every kid growing up had for a few decades where the newspaper would be out on the kitchen table and the kids would nosedive for the comics. When I think about it, it was a brilliant move for newspapers. As I got older and closer to being an adult, I started reading the rest of the paper.

There were several excellent comics, but only C&H has stood the test of time and I am so proud that my 8 year old daughter recently pulled down the books are started getting lost in them. Sometimes the restrictions and limitations produce creativity in their own right, and I often wonder if something like C&H could even make it in today's cultural environment (both from a political point of view and in the modern social media landscape).

TIL that Bill Watterson is still alive.