ktuos answered: Because appealing to the lowest common denominator with crap gets more money confusing them with smart writing or aiming for a niche market

Yes, and it’s a sad truth.  The worst part is that this is not only a self-perpetuating issue, but one that has become more and more common on certain networks in the past few years.
It’s just a sad thing to see shows get a LOT of press to turn out terrible and only last part of a season while other shows are lauded, yet die too soon because their networks didn’t advertise them.