Why aren’t self sustaining edible guilds everywhere?

Could this not essentially feed communities for free?

Edit: I think I received the answer from everyone’s posts- thank you! “Self sustaining” still takes enough work that we don’t know if/how the community will step up. Rising the permaculture trend and sharing information/education seems to be the only way forward.

Edit 2: just want to share my favorite quote, that I often revert to, for whenever it feels like things can’t get better:

“Optimism is a strategy for making a better future. Because unless you believe that the future can be better, it’s unlikely you will step up and take responsibility for making it so. If you assume that there’s no hope, you guarantee that there will be no hope. If you assume that there is an instinct for freedom, there are opportunities to change things, there’s a chance you may contribute to making a better world. The choice is yours.” Chomsky