it would take a lot more discussion to explain all the reasons (such as the confluence of the motion picture vertical monopolies being broken up,
the rise of TV, the UPA influence, the fall of many cartoon studios (WB MGM and Terry returned under new management several others like Universal/Lantz continued to make shorts into the late 1960s) that a cartoon like Colonel Bleep came about and found a home in the 1st decades of TV - mostly monetary, some artistic - it is a OK program (which had some input from Joseph Barbera) - it’s weak compared to really good programs from Jay Ward or even H-B but looks like a classic next to poor contemporary fare like “Clutch Cargo” or “Bucky and Pepito”
Some of that stuff was intolerable. The frame would remain the same while dialogue was limited to lips movement. The whole damned show might only have half a dozen scenes.
plus TV could do a 30 minute story instead of a cartoon short. Like Tom Terrific or Crusader Rabbit.