Pyramids are really not that hard to make, they certainly don't require high intelligence. After all, a pyramid is literally the simplest possible mathematical way of making a tall, stable structure.
Now if the Egyptians/Mayans etc had built skyscrapers with glass, metal etc. you might be onto something. But they really are very simple structures, that anyone with basic knowledge could build. In fact there are many crappy pyramids in Egypt, that predate the more advanced ones in Giza etc. But we don't hear much about them because they are so crappy.
Look up the shit pyramids of Sneferu as an example.
It's a complicated thing with those pyramids. They might not be hard to build, but there's no way to transport such heavy blocks without the use of machines.
Stone blocks used to build pyramids were enormous even for today's standards. The biggest one in the base of Chephren pyramid weights 468 tons (!). If you ask people how the pyramids were build they will usually repeat the silly explanation they saw on TV: "Egyptians pushed them across the desert and lifted and positioned with the help of cattle and wooden cranes."
Transporting a 70 ton granite block would require over 600 workers, a 200 ton one? Just over 1,8 thousand people, and that's less than half of what we're talking about. Now if they even managed to somehow pull it off there was a problem of pulling some of those stones up and fitting them into the walls and inner chambers.
To give you a perspective a typical 80m crane you see daily in almost every city in the world has a maximum lift of 20 tons and the weight of a locomotive is close to 150t.