collapse of the old society

f you don’t have artificial fertilizers, tractors, refrigerators etc etc, there is no way people can be fed even if they are everything that nature created.

David R. Montgomery puts forward some interesting evidence that the world could be fed without industrial farming, and there are promising new methods of creating artificial fertilizer using renewable energy instead of the fossil fuel using habor-bosch method.

Cities are giant factories that require the constant cycling of goods (food, water and other materials) using a transportation grid and they also require constant energy inputs to remove waste materials.

Cities use far less energy and materials than less dense suburbs or rural living, which require moving materials and energy further than cities to dwellings that are far less energy efficient. I get the feeling you didn't actually look at the links I provided regarding how with the right planning, cities could be made self-sufficient and the most sustainable way of living, as you continue to suggest that they cannot be, even though the math in those videos indicate the opposite.

so your idea about edencity and public transportation is like you almost see how unsustainable cities are, and why.

I never said cities as they exist today are desirable or sustainable, nor was that the inquiry you made to me. You asked what existing technologies we had to live sustainably. I think I made a solid case that we do have the existing ideas and technology to do so, but they are simply not implemented for reasons unrelated to their actual technical viability.

on a planet where we cannot feed, build houses and build transport for everyone

And this is a completely artificial social problem, not a technical one, which is what I've been mentioning in each response.

Capitalism is ultimately responsible for a tremendous amount of that artificial scarcity of food, housing, and transport, as profit incentives cause powerful corporations to suppress or eliminate solutions that would jeopardize that profit. Farmers during the depression destroyed food while the hungry watched to protect the market, affordable housing isn't created because it isn't as profitable as expensive housing, rent caps aren't implemented because real estate monopolies and landlords lobby politicians to ensure their profits continue to rise, public transport was gutted by monopolists in the oil, car, and tire industry for their continued profit.

As long as capitalism rules us, we will struggle to implement the tools that could save millions of people from dying, all for the benefit of a few psychopaths. I strongly believe we will continue on the path of destruction unless there is a nearly global rejection of capitalism as the main form of societal structure. I don't know for sure if we will eventually cast it off and survive, but I'm sure as hell going to try to slow down the amount of emissions we spew out in the hopes it gives us a sliver more time for that to potentially happen.

Whether or not you believe it's possible for humanity to actually do that depends entirely on how cynical your worldview is. In practical terms, a fully cynical view only guarantees a fail-state, which doesn't seem like a useful mindset to have. So I will continue to do as much as I am realistically able to help the possibility of resisting capitalism, as it's our only real way out, and I'll be happier with myself that I tried, even if we fail.