When I watched cable tv in the US in 2007, and while watching cable tv in Australia in 2015 (which is mainly made up of American channels), I noticed that a lot of the documentary channels (channels about history, science, nature, and the like) had a lot of shows that either
- Were reality tv in format, such as Ice Road Truckers and Deadliest Catch.
- Were about "controversial" topics (I'm not saying "Ancient Aliens", but "Ancient Aliens")
Have US cable tv documentary channels always been like this? If not, what caused the change?