I'm talking about TV shows that were initially quite popular and really seemed to capture the zeitgeist but which have now faded more than one might have expected. The fading is especially poignant if the shows were actually pretty original.
Baywatch was the greatest pop culture show in history during it's run. It's not showing anywhere, was of it's time, and is dead and buried now. Or "disproportionately forgotten" as the op said he wanted.
Don't want to start a pissing contest. All reasonable candidates. The reason I picked Maxx Headroom was that he was a cultural icon in the early 80s ad then faded into nothingness overnight. Basically, technology caught up with and passed old Maxx. The other shows mentioned are available online or in syndication. Good old Maxx is pretty much forgotten. I suspect he is too long ago for many of you.