Most importantly, Bill Hanna developed The System: a means by which great amounts of footage could be generated over a short period of time at a reasonable cost. TV cartoons could not have succeeded without The System, period. Say what you like about the quality of the product, but The System changed forever the manufacture of animation, and allowed a cottage industry to enter the larger market. The networks could order in one season more animation than had been made industrywide in the entire decade of the '30s, and have it delivered ready to air within months. Revolutionary.

The other factors pale by comparison, but deserve mention nonetheless. One was the inherent repeatability of animation at a time when videotape did not exist; live shows on film could and did repeat, but tired much sooner, and had none of the excitement of the then popular "live" kiddie TV. Another was the ease with which animation passed over the barrier between Black & White and Color TV: cartoons had a long history in color, and additional costs were minimal, mainly in the areas of film stock and lab work. (Live-action had to rethink itself completely for the change to Color TV; costs went through the roof.) And there was SAG: Ronnie Reagan (he was President there first and he'll be back in this story in a later role), residuals (and the lack thereof in animation), etc. It was just plain easier in the fringe area of kiddie TV not to deal with those actors, and cheaper too.

There was also a need, a need that will be a recurrent theme through what follows: advertisers wanted those young eyeballs, they wanted them on a national basis, they wanted them without dilution (no adult viewership or interference), and they wanted them all at the same time (or at least day-and-date). As other audiences dominated weekday dayparts at a time when most houses had only one TV, there was only one time that need could be met: Saturday morning. (And Sunday, too, until news took over.)

So, throughout the later '60s, animation came to dominate the airwaves on Saturday morning. Advertisers were happy, as they could and did dictate (informally if not directly) what cartoons got on the air, and soon they began to recognize the real power of TV in selling to kids. And the networks were happy, too; the (then) three networks shared over 90% of the kiddie audience, and even third place made money, lots of it, as the scarcity of available national commercial slots (only Saturday and Sunday mornings, for the most part) lifted prices on a consistent basis.

Before we get lost in the haze of nostalgia, let's remember that the '60s/early '70s was a mixed bag of TV cartoons. Some of what was made then is now cherished, but much is forgotten, including one show especially, although it made its mark on the industry for the next 15 years: Hot Wheels. The advertisers had come to dominate kiddie TV content to such an extent that the FCC finally took notice, and this show was to the FCC the last straw: "program-length commercials" were forced off the air. But not forever.

This FCC pressure was just one of several forces which pushed animation into decline in the early '70s. The premiere of Sesame Street brought more pressure on the networks to clean-up kids TV, to make it more "educational" and "real." As networks always want to have peace on the political front, orders came down from on high, and the industry entered the great pabulum era. More live action, more social relevance, more lessons, more BS&P strictures, more boredom. (Please understand that I am not taking sides on the content argument; these are just the facts.)