True, but remember that the orbits above LEO are also full of junk that will eventually be coming down through LEO before deorbiting. So despite the short lifet

True, but remember that the orbits above LEO are also full of junk that will eventually be coming down through LEO before deorbiting. So despite the short lifetime of debris there it'll still be a long-term problem in this orbit as there'll be new junk even if we would stop orbiting stuff. There'll be crap coming down for thousands of years, including some nasty cold war relics like nuclear reactor cores.