Hmm. I tended to interpret the remarks that less food is necessary at "level three" because buildings, techs, and civics will have made local consumption and generation more efficient. And meanwhile, housing limits will put a firm cap on growth. No point in having lots of farms generating food if you lack the needed neighborhoods to raise the population ceiling.
Wonder will eventually become of aqueducts? They'd be pretty anachronistic in a post-industrial city, so perhaps they too become neighborhoods.
