I guess this is why DC has to resort to the subscription service coming out soon. Even if DC made more cartoons the schedule for CN wouldn't work since they've been getting rid of 30 minute slots. And they sure as hell ain't making room for JLA.
Honestly I think DC/WB, in making JLA, did a lot to try and work within CN's parameters (more emphasis on humor and fun, 11-minute episodes, etc.) but even that didn't seem to help them in the long-run.
But yeah, I think it's more and more likely that DC is going to be releasing a lot more exclusive cartoons on the service since they can't seem to trust CN with anything that's not Teen Titans Go!.
Though supposedly the Lauren Faust DC Super Hero Girls cartoon will still premiere on Cartoon Network.