I've long had a scifi vision of the future in which autonomous drones intelligently, with sustainability as a goal, hunt wild fish as a good way around the factory meat problem. Only slightly related, just wanted to share some techno-optimism.

Techno-Optimism nowadays includes Hunting Robots. What a time to be alive.

True, but it doesn't scale. Good luck if you live in a metro area.

How so? In San Francisco there are several local produce markets within walking distance of where I live. Whole Foods and Trader Joe's are pretty common major grocery chains here, and there are two weekly farmer's markets I can think of that are accessible by bike/transit.

When I visited Manhattan/Brooklyn recently I didn't get the sense that they were lacking in locally-sourced foods either. Main problem I can think of are food deserts, but those are more of an economic problem than scale. When I used to live in one in Baltimore though it was possible to find local food, it just took more effort.

this part specifically:

> growing your own food

I should have quoted that directly in my original comment.

If there was demand for it, every other apartment building rooftop could include a greenhouse.

you would need much more than a rooftop to feed a high rise apt building, no?

Correct, but a rooftop would put a sizeable dent in the building's need to bring in food.