"The timeline is always being adjusted, through the work of archaeologists. To quote a now famous Hancockism, “stuff just keeps getting older.” Yes, and it’s archaeologists that you have to thank for that. Stuff keeps getting older because we keep looking for it, and because we keep analyzing it, in the plain light of day, not in somber academic conclaves where we decide what should and shouldn’t be revealed to the huddled masses, presumably living in fear of the next apocalypse."

Hancock is hijacking peoples attention and funding. The money that went into making this season would have been much better allocated to various archeological digs. That way, more actual work and analysis could be done as opposed to Hancock's tenuous theorizing. Archeology is always evolving, that doesn't mean big archeology is lying to you. It just means they are presenting the most logical evidence they have at the time, and when new (well documented and analyzed) information comes along that changes.