I was just reading about a "9-11 Truther..."

[NCTraveler]

18. They were truthers on day one.

Without evidence at all. They literally started appearing on day one. Their "evidence" has been beyond debunked. Those real truthers are few and far between at this point. Fact is that they are anti-science. They have proven it over and over again. They determined what really happened, then looked for information to back them up. That in itself will lead one down the wrong path almost every single time. It is how Fox News reports.

You are right that their numbers and presence have greatly diminished. Many of the initial truthers were not stupid people. There were many reasons to question motives at the time. That coupled with all of the misinformation made some form of conspiracy fairly easy to believe. In the end, that group settled on the facts available and within somewhat short order became one of those calling the truthers stupid.