I think people understimate the wonders that increase commerce cap. Think about how much people spend to increase their cap by +50, particularly as the game goes on.
- PYRAMIDS - Increases your Commerce Limit for Food and Wealth by +50, & Improves your Food gather rate by 20%
- COLOSSUS - Increases your Commerce Limit for Wealth and Timber by +50, & Increases your Wealth gather rate by 30%
- TEMPLE OF TIKAL - Raises your Commerce Cap for Timber by +100, & Increases your Timber gather rate by +50%
- ANGKOR WAT- metal commerce cap +100, & Metal gather rate +50%
- KREMLIN - timber, food, metal commerce caps are +200
- TAJ MAHAL - wealth commerce cap +300, & wealth income doubled
- EIFFEL TOWER - oil commerce cap +200, & oil gather rate +100%
This is in addition to all the other effects. I may make some of these more often. Imagine Egyptians building Pyramids and Colossus in Ancient and effectively gaining a +50-100 econ advantage for the rest of the game! That alone would pay for successive wonders, which would pay for the ones after that!