To those of you old enough to remember, when color TV came along, it took quite a while before most programming could be viewed in color. As I remember the same scenario took place. Network programming gradually switched as more and more people purchased color sets. The local's took longer because color camera's and transmitting equipment were quite expensive.
I remember the first color program I saw was "I Dream of Jeannie". It's kind of hard to forget seeing Barbara Eden's genie costume in "living color", especially when you're a 12 year old boy.