The major ideologies have developed through history. Each of them provides the conditions which permit the next one to emerge, and each of them has fewer people attached to it than the one before. Also, a pyramid is notably static, the ideological system dynamic. Different parts of it change at different rates, and for most social purposes its overall form can be taken as stable, but no part of it is permanently fixed and neither is the whole.
Power is possessed and exercised mainly by the big numbers towards the foot.
The late George Walford, upon whose writings the above is based, worked extensively with systematic ideology. You can give a rating to this scheme overall. Click 0-10 below and press the Submit button. DoBe.org or click on the image below.