The Ancient Alien Bandwagon

I'm a long time watcher of the History Channel's Ancient Aliens.  There have been many regular 'talking heads' on that show for some time.  However, upon reading their own published works, I've discovered something rather interesting.  Many of the guests and 'talking heads' that come on the show with Giorgio Tsoukalos (a true believer, heir to Erich Von Daniken, and closest thing to a 'leader' in the Ancient Alien Theorist community as you can get) don't actually believe what they are saying when they appear on Ancient Aliens.  For instance:

Graham Hancock:  Very clearly states in his books that he thinks there was a prior human civilization (or civilizations) on Earth that got to a very high level of technological development but then disappeared due to war and/or natural disaster.  Atlantis was one of them.  But no alien interventions were needed and probably did not happen.

David Hatcher Childress: While giving lipservice to the possibility of ancient aliens, his views are very simular to Hancock's.  There were flesh and blood Ice Age (or earlier) human civilizations which are now lost in the sands of time.  

Phillip Coppens: Sadly, he passed away in 2012, Coppens writes in his book, The Ancient Alien Question, that he very much doubts there was actual physical contact between ancient humans and ancient aliens.  If there was some sort of contact, it must have been channeling or some sort of spiritual communication.  

Andrew Collins: In his books "Gobekli Tepe: Genesis of the Gods", he refers to the ancient alien theory as a "fanciful notion" which he does not hold with, in this book at least.  Collins sees a world-wide disaster occurring during the Younger Dryas Boundary (when mega-fauna went extinct in huge numbers such as the sabre-tooth tigers and mastodons).  This disaster, probably a meteor or comet, caused shell-shocked human survivors to wander the world.  One such group which already had knowledge of astronomy and agriculture, arrived in the middle east and swiftly became the elites of this area through coercion and conquest.   They were behind Gobekli Tepe.  No aliens, just a slightly more advanced human culture from what is now Southwest Russia that moved down into East Turkey and Northern Iraq.   Collins does stray more into the Occult than Coppens does but still does not think aliens had anything to do with us.

So, it seems to me that when these writers, and others, appear on Ancient Aliens, its only in the understanding that they will agree with the subject matter.  Whether anyone with the show knows their true beliefs, or cares about them, is anyone's guess.   I figure that as long as they tout up the ancient alien line when they come in the studio and make the show interesting, they are welcome.