No, this isn't stating the obvious, it's cheap, unthinking cynicism. In reality, TV shows compete against each other very aggressively, and having more complex, interesting, realistic characters can and does bring a huge competitive advantage to one show over another.

TV shows do compete aggressively, but having complex and realistic characters is only a good investment for the small minority of shows that are highly serialized and oriented around complex characters (Mad Men and Breaking Bad are good examples). There is a market for shows like this, but it is small and not terribly profitable.

The big money comes from shows with simple cardboard characters and one-off storylines like The Big Bang Theory (which set a record for biggest per-episode syndication deal ever) and Baywatch, which was syndicated in 142 countries. They have mass appeal and--most importantly--are easy to sell into syndication, where they become permanent cash cows.