Bikinis? That's an unusually chaste idea.
Although in all seriousness, Starz exists, and HBO includes sex and swearing in almost every show like it's the cable channel's watermark.
Demands? No. Accepts and is entertained by? You got it. It is called the lowest common denominator for a reason.
That's basically it. How many people are buying the DVDs of the pseudohistorical shows or declaring them their favourite things on TV? All a network TV show needs to survive is just enough people watching and entertained for whatever reason. How much they're entertained by it and the level of their engagement will vary.
But realistically, who turns to TV for historical documentaries anymore? Even ignoring the written word (and quite frankly that's automatically preferable for any pre-Lumiere brothers history) I can usually get better documentaries through stores or online. You're not got going to find something as good as Fog of War
as TV programming anytime, ever.