iirc Beware's case was a result of CN just scrapping their DC Nation block entirely, and AS airing them because they were already finished. The Teen Titans GO! shorts, as well the full series created subsequently, were the only real hit they had with that DC effort. Young Justice and GL: TAS were both infamously axed due to low merch demand.

So it might just be a case of shows skewing older like you said. CN has done this before back in 2004 when Toonami moved to Saturday nights, as demos were skewing a little older and concerns about violence were giving some folks at CN cold feet.