What I mean is that while it was popular among people of a certain age (i.e. born before 1980) or older who used to watch the program when it aired originally and also in syndication decades ago, the series has arguably never really caught on with most people born after 1980. And it’s now only aired on obscure cable channels in the United States. It may not even be airing daily any longer like it was in the 1970s and 1980s.

I mean according to TVGuide online, there are no airings of the series listed for the next 14 days (As of July 14, 2019)

The Brady Bunch | TV Guide (https://www.tvguide.com/tvshows/the-brady-bunch/tv-listings/100453/)

It’s still airing on MeTV regularly. I think it’s still popular. The show is still popular generations after the show airing. I was born after 1980 and love this show!

It may not get watched as much from being broadcast because many fans of the show have bought the series on dvd.

I tend to think, there are so many shows to see. Also too many younger people may find the show to be too goody goody. I am Peter Knights age and I could relate but times have changed. Kids with tattoos, smoking, swearing, clothing styles, kooky hair . The show was in its own time zone.

I haven't watched it in a long time but I still love it.

Perhaps younger people enjoy it in an ironic sense.

It may not get watched as much from being broadcast because many fans of the show have bought the series on dvd.
That's true.

All shows eventually decline. Even “I Love Lucy”, one of the biggest hits of all time in syndication, is tougher to find now than it was 10 years ago. “Lucy”, the Bradys, and “Three’s Company” have had amazing lives in syndication. But they are not going to be hugely popular forever.