Your precedence note is fair but it seems likely the whole "ancient aliens" subject was in the air around that time; pseudohistory has existed as long as history and this particular strand just emerges with the sci-fi boom and particularly the post-war fascination with UFOs.

Von Daniken was obviously just particularly good at pushing his brand of the nonsense; all of those authors though are interesting examples of the sort of anti-academic and conspiracy theorists that have reached their apogee in recent years via social media.