I think a lot of the anti-vax conspiracy stuff got tested out in the 9/11 truther stuff. It was almost like a training in how to sell a message to the masses and how to find the things that work, and the things that didn't. It also has really helped that China and Russia have gotten way better at figuring out how to sell death to Americans as a patriotic thing, and a ton of Americans are swallowing it hook, line, and dewormer.