The problem with the pyramids-as-evidence theory is the design of the pyramids themselves. Certainly, they're all huge, and have the essential pyramid shape. However, you can immediately tell that there's a huge difference between one of Egypt's grand tombs and an Aztec edifice. For one, they had completely different applications. Egypt's pyramids served as tombs, and represented a ray of the sun. They weren't meant to be climbed, and had smooth sides. Precolumbian American civilizations, on the other hand, designed their pyramids as practical everyday-use temples - they had steps, decorations, and a large platform on top which acted as the temple proper. It did not represent a ray of the sun, but was used as a way to get closer to the sun.
Finally, the biggest problem is the times involved. The great imposing pyramids of Egypt were built mostly between 4000 and 3000 BCE, whereas most of the Olmec/Aztec/Toltec pyramids were constructed around the time the Crusades were raging in medieval Europe.
I might quibble about your word choices. I would prefer to say, "For many practical purposes, it can be considered linear." But then that's the pedant in me quibbling about a minor point that for all practical purposes is not worth quibbling about. Anyway, thanks for clarifying what you meant, and also for putting up with my crap. 
