Usually not - modern landfills are completely enclosed (sealed in plastic) and primarily composed of things that don't compost at all, like metals and plastics.

Usually not - modern landfills are completely enclosed (sealed in plastic) and primarily composed of things that don't compost at all, like metals and plastics. The materials in a landfill aren't recovered. By comparison, the point of composting is to break down the organic waste where it can be reused as soil and fertilizer.