What is a Hanna Barbera television show doing on a Disney focused website? Well it just so happens that the very first color broadcast from Disney's current subsidiary ABC was Hanna Barbera's The Jetsons.
ABC was late in getting color on the air. In fact, Walt Disney moved his show off of ABC because the network was not yet broadcasting in color. While it was true that ABC was the poorest of the "Big Three" with the lower tier affiliates, the truth was that hardly anyone owned a color television at the time. The vast majority of the people watching these shows would not be viewing them in color, so ABC sat things out until much later than its competitors.
So why would NBC and CBS push color onto their viewers and affiliates? It was pretty simple, really. NBC was owned by RCA, while CBS was owned by Westinghouse. Their parent companies made and sold color televisions. ABC was the only network that had no ties to a television manufacturer and therefore had no real incentive to broadcast in color until viewers began to demand it.