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

Don't they do that in China already? Could've sworn I've seen a post here about it. Essentially, agricultural workers live in proper high-rise apartment buildings, with all the urban infrastructure it requires, but work in the fields and whatnot right outside the town border. There's no suburb layer, and no need for discomfort.