In part, this is a reflection of the discredited view that human history follows a linear progression from technologically unsophisticated to sophisticated; only the destruction of a civilisation can lead to the loss of a highly-developed technology. This is not the view of mainstream archaeologists, who understand that complex societies can collapse for a variety of reasons. This sort of systems collapse will impact on many, if not most or all aspects of society. A highly organised state system that is able to manœuvre large numbers of people for construction projects can disappear almost overnight. Bad Archaeologists are unwilling to do the background research into the societies that produced the monuments they present as mysterious, so either they do not appreciate the evidence for ancient complex societies or they deliberately withhold this evidence from their readers. What is more pernicious, though, is that while they can accept that locals (Greeks, Romans and so on) were responsible for the ancient monuments of Europe, they are unwilling to countenance the same explanation for people on other continents, especially Africa and South America. - https://badarchaeology.wordpress.com/2014/01/12/is-pseudoarchaeology-racist/