"What remains: not much, really. Some glass, stone, metals. Not much that burns well."
I'm not sure what country you're describing, but here in the Netherlands, we separate paper, glass, plastic packaging (PE, PET, PP, PS), organic waste, electrical equipment, chemical waste. Stones (e.g. from breaking down a wall) are not supposed to be mixed with household waste. Laminated materials such as potato crisp bags and milk cartons, styrofoam, discarded household items go into the "other waste" bin. I'm not sure whether I'm supposed to, but plastic with food scraps sticking onto it don't make it to my plastics container since I don't want them to rot and smell. My trash bags will burn pretty well.
For the Netherlands, I think company offices are a big contributor to incinerable waste. They separate the paper, but not the plastics. Many company restaurants are not separating compostable waste from what the employees leave on their trays.