What was the best single network one-night primetime lineup ever? That is, you could tune to channel X at 8pm and watch straight through to 11pm without once being bored or wanting to flip over to another channel? (Adjust hours for Central, etc.)
My nominee is the CBS Saturday night lineup in 1973 :
8:00 All in the Family
8:30 MAS*H
9:00 Mary Tyler Moore Show
9:30 Bob Newhart Show
10:00 Carol Burnett
The demographics have changed. Or, I should say, the demographic groups the networks are trying to woo have changed. In 1973, the people the networks loved were the middle-aged 40ish to 60ish folks, who stayed home on Saturday nights. So they programmed well on Saturdays. Today, it’s the 18-30ish demographic the networks can’t get enough of, and that demo is typically NOT home on Saturday nights. The networks aren’t going to waste a powerhouse show (and the advertising draw it could be) on a night when their most desirable demographic isn’t even home to watch.
Seeing as how the OP did not disqualify radio from consideration, I’d argue for Thursday nights from 8 to 11 PM on the NBC Red network during the 1932-1933 season, at least in pure rating terms.
All three shows that made up that time slot (The Jack Pearl Show, The Maxwell House Show Boat, and The Fleischmann’s Yeast Hour) finished in the Top 5 for their season, and received 30 or more rating points from the CAB.