What made the television series “My Three Sons” last for 12 seasons?

[TMC]

Why did it change networks during its run? Why was the show finally cancelled after 1972?

[biffbronson]

Originally Posted by TMC

Why did it change networks during its run?

ABC dropped the series because network series were switching to being filmed in color, but they were too cheap to do so for My Three Sons. So the all-b&w ABC run ended after Season 5, with CBS's color Season 6 picking up without interruption.

[stevea]

Originally Posted by biffbronson

ABC dropped the series because network series were switching to being filmed in color, but they were too cheap to do so for My Three Sons. So the all-b&w ABC run ended after Season 5, with CBS's color Season 6 picking up without interruption.

This was not a good move for ABC, since it was a top 15 show in the 1964/65 ratings. ABC should have gone with color for Sons, and maybe have said no color for Ozzie instead.