I could see removing smaller buildings and replacing them with more greenery, and maybe building some sort of self sufficient sky scrapers in a wilderness of food forests that used to be monoculture. However, I don’t think it’s practical or necessary to remove existing urban infrastructure and build vastly more across all wilderness. In addition vertical farms and forests can be made in cities, so again not exactly necessary. Obviously we should make sure rural people have everything they need within biking distance, but we don’t need to take it to the absolute extreme.
I think Engels was more referring to building up the rural as opposed to breaking down the urban. And I support him in this. A chain is only as strong as it’s weakest link, and the contradictions between city and country have caused far too much damage as seen in today’s neoliberalist America. Maintaining this moving forward would be asking for trouble later down the line. We must balance the development to remedy the contradictions