https://www.bloomberg.com/news/features/2023-07-07/in-quest-for-food-security-cities-test-limits-of-urban-agriculture?
In Paris and elsewhere, cities are exploring the economic and environmental benefits of building-based agriculture and racing to protect farmland at the urban edge.
Yes, it's about how far they should be importing from. Many could probably do 80% of vegetables within ~20miles if the land around cities was used for horticulture rather than horses.
I agree with you on this. Once you get past the suburbs you can grow. I'm not going to give any links or anything, but all of the old cities and towns used to be ringed by agriculture. It could be viable again.
That's just me woolgathering.