Looking through the historical prime time tv schedules over the last 30+ years,
I just came to the realization that I hardly recognize any of the NBC shows over the last 25 years. (Other than Law & Order).
Though for that matter, I hardly recognize any of the shows on ABC over the last 25 years (other than MacGyver), and I don't recognize many of the CBS shows from the late 1980's through to the early 2000's.
(I didn't really pay much attention to FOX and other networks back in the 80's and 90's, due to not always having cable or crappy ota reception of other channels).