I feel like it's more because CN America hates every show they have except for TTG. Basically the current top guys inherited the tweens-teens demographic that Adventure Time started pandering to, and all the cartoons that followed it.
Now, in part because of CN's autism (and now that I think about it quite possibly because of executive mandate trying to make TBS's animation block Turner's new 13+ animation guys) they want to shift to a waaay younger demographic, younger than CN's ever pandered to, and as a result CN literally has no shows that they can play. They give Gumball lipservice because it isn't as bad and PPG and Ben 10 were supposed to be the "boy toy" and "girl toy" factories so it didn't really matter how much airtime they got, and Mighty Magiswords is progress, but outside of that all their other shows (current and cancelled) are either too edgy, too quiet, or too smart to drag toddlers away from their tablets and endless stream of Let's Plays and Finger Family vids.
I suspect that if CN could, they'd cancel half their lineup right now and half their upcoming lineup, but because of unknown under the table shit much of these shows (like Steven Universe) are safe, for now, and are instead being slowly phased out.