I still watch. I never stopped watching. It looks like it averages 1.7 million viewers on average, which has been decreasing over time.

I don't really hang out with people under 30, but they're missing out. Sure the new episode are just good, but the classics are still the classics.

But also at 34 (and counting) years it's the longest-running animated American series, longest-running American sitcom, and longest-running scripted primetime series. Never having heard of it is a huge gap.