THE COST IS TOO HIGH
I was reading an article about what killed the Saturday morning cartoon. Back in those days, to produce a half hour of television cost as much as $330,000 USD. That was the 80s. Today a show like Avatar: The Last Airbender can cost as much as $1 million per episode!
The cost of producing animation is just too high. At least, that's the case if you do it the traditional way, the studio way. There is another road. The indie road! You don't need millions of dollars or major studio backing. You can create the show you want to create. The tools are available to everyone today. And you have no idea what kind of interest you may attract if you do so!