NickToons premiered in 1991, so forget CN. They weren't relevant till the late `90s and are currently the #3 kids channels.
You're SORT OF correct in the "cartoon" area, but Nick has had an ENTIRE line-up of original content since the start of the 1990s. They had original kidcoms, game shows, and sports shows. As well as the Nicktoons. And most of those shows were popular with kids. Yet it didn't affect network ratings. It didn't affect Power Rangers and Pokemon from becoming the #1 kids shows.
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