In the US? We have never been given harmful, ultra-processed food here, let alone pizza. The differences are wild. Pizza costs a lot here, to be honest. It is cheaper here to just make food from scratch from fresh, healthy ingredients.
Pizza is flour, tomatoes, yeast, salt and cheese with a splash of oil. Cheese is heavily subsidized by the us govt so the only expensive piece is tomatoes. It's made on an assembly line and shipped out as frozen slabs or as constituent ingredients that are then baked on demand.
Fresh tomatoes are cheap here, although I have to admit their taste has deteriorated over time. The canned ones are better to use as an ingredient due to this reason.
The US has a lot of 'food deserts', areas where there's no easy access to a supermarket with fresh food. But there's usually plenty of fast and processed food available, and it's often cheaper than fresh.