I think I understand what you are saying. My reasoning was that right now we are using good farmland for frou frou crops like lettuce that have a quick turn aro

I think I understand what you are saying. My reasoning was that right now we are using good farmland for frou frou crops like lettuce that have a quick turn around(45-60 days)..they use a lot of fossil fuels, have to transported long distances and involves labour exploitation for very low calorie/nutrition. And then strawberries that require the soil to be fumigated with really nasty stuff like methyl bromate fungicide. These are kind of crops are better grown in urban spaces indoors and vertically where there is soil already contaminated and is essentially warehoused. Using solar, better led lights and maybe hacks like placing them near water treatment plants etc can be a good optimization of energy and resources that are other wise underutilized. Further aquaponics that is also fish farming is even more environmentally friendly as it’s a closed loop system with minimal inputs. By marginal lands, I mean abandoned factories and soil contaminated with heavy metals that is difficult to remediate without a lot of expenses. Growing highly perishable produce like lettuce and strawberries indoors in these spaces is a win-win. My 2c. I dream of little nuclear ‘suitcases’ that can power cities for weeks or months. Factories that can be run with solar as well as nuclear energy. Hopefully we will find a way to dispose and dismantle nuclear installations safely in the future. Your other point: if we are to emulate nature and get back closer to natural growth and evolution of civilization as we know it..we could model it around the Nile valley or the Indus Valley. I think having clusters of small self sustaining villages with intra trade and further away trading for other wgat we can’t produce is better. If we can create village clusters networked to other clusters connected together to bigger and bigger fractal systems of both tech and environment and wilderness, we can have it all. In the future, a lot of trade would be services. For small scale sustainability, we would need automation. This frees up labour force to do other things. Even a simple adjustment like a 4 day work week or 20 hour workweek or working remote would have a massive impact on how we consume and our collective footprints.