TV doesn't care so much about high ratings so much anymore. The goal now is to get fair ratings enough to get to 100+ episodes for DVD, downloads, and foreign sales. Syndication is still big but not what it was.
Your post is VERY accurate. They make tons in syndication so even if they get so-so ratings they will make money which is why for example Parks and Rec and Community are still on the air....waiting for that magic 100.