Non sequitur, Regular Show went for 8 seasons, and Adventure Time which also started in 2010 is still going. Steven Universe which started in 2013 in currently in its 5th season, all Cartoon Network shows that exceeded 65 episodes.
Okay, those are all more recent than my experience with CN, so maybe their policy has changed. I was thinking of their various Batman series, Ben 10, Scooby-Doo, and the like. I should've offered the caveat that my experience with Cartoon Network is a bit rusty, since I don't think I've watched anything on there in a few years. But I guess I didn't realize how long it had been.
But the core point remains, that it's not exclusively a Disney practice to end kids' cable shows after a few years.