I think the pyramid thing is either just a case of:
1) If you were going to build something big and tall, yet stable, a pyramid would be the way to go. We didn't really get into building skyscrapers until the mid-1800s, so it's not that hard to believe that it was just natural ingenuity over time that caused this worldwide pyramid phenomenon, especially since they all aren't uniform in design.,
2.) it could possibly tie into the idea of us being one big consciousness. I recall hearing about a study with rats in a maze, and how rats in location A and B are put in the same maze pattern, the rats in B figure it out in a shorter time, and then so did the rats in A. Then, however, when they started to use rats that hadn't been in the maze, they were still doing it in shorter times, as if the entire species learned to navigate it because the first one did. I'm probably butchering the story, and IDK if it's true, but that's what I heard.
3.) Since one of the strengths of our species is being able to collect and build upon previous knowledge, we could have been building similar things for as long as we've been human and as we migrated, we never stopped. Like if two friends grow up together until the age of 5, and one moves to California and the other one stayed in Alabama, sure they are far apart and sound a bit different, but they both are still speaking English.