Actually, it wasn't NBC who were the vulgar guys--in fact, during the Pat Weaver era, it was to the contrary. It was ABC that played the brash card, with their deals with Disney and Warner Bros. for exclusive programming when Hollywood didn't want anything to do with television, that put on "American Bandstand" when most of mainstream show biz wanted to treat rock and roll as a fad and most importantly, decided to aim their programming at younger demographics because they thought it was the only way that they could stay afloat. (And for our purposes, they were the ones that gave Chuck Barris the greenlight to do a game show that could've come from Hef's place and to take a dowdy little format concept about newlyweds and tart it up into a hit.)
What happened was that ABC's innovations became so imitated by everyone else. A lot of people who have studied business have come right out and said that every broadcast network today is working out of the ABC 50s and 60s playbook. If you don't believe me, try to find "Omnibus" or Leonard Bernstein (or "WML?", for that matter) in the current network lineups.
