Aren't little bits of debris in LEO going to fall back into the atmosphere and burn up pretty quickly, though? Not an expert here, but I think there is enough atmosphere left at standard LEO altitudes that thrusters are needed semi-regularly to keep these things in orbit. Granted, some debris may get launched into a weird elliptical orbit that takes them farther away from Earth for a bit, but then won't they come right back into the atmosphere at perigee and burn up?