I would assume that civilization doesnt collapse like a building, it collapses like an ecosystem, slowly components of that civ don't have the resources to exis

I would assume that civilization doesnt collapse like a building, it collapses like an ecosystem, slowly components of that civ don't have the resources to exists, services go unrendered,people stop living in that area, pressure builds on less affected areas. Costs rise, gentrification pushes low income people into bad parts of town, that compound and get worse.