Yes the objection to Cladking's general idea of a C02 geyser being used to power the device. That an any water weight system won't work as you have the difficulty of bringing the water up first, if that could be solved it might be a usable system.
One: I believe they used our different methods, direct drag to the site (for the first tiers)
Two: Ramps from base to pyramid
Third: a switch to an internal/external ramp to take the stone higher while using the lower ramps as the main feeders
Fourth: At the highest levels some sort of shadduf or other type of 'machine' to lift the final tiers.
A weight based system could replace many of these if a way could be found that explains how the weight is moved up that doesn't increase the work.