Well the clean-up problem get's even more complicated with MEO and beyond as the amount of space becomes even larger. As for space-junk not being a problem in L

Well the clean-up problem get's even more complicated with MEO and beyond as the amount of space becomes even larger. As for space-junk not being a problem in LEO, you are correct that space junk in LEO will de-orbit in a somewhat reasonable time-frame (on the order of a few years), but that's still problematic. It would still cause the destruction of 100s of billions of dollars worth of equipment, the ceasing of any operations dependent on LEO satellite equipment, and either increasing the risk or out-right blocking launches through LEO for a number of years. The fact that this would be temporary does not mean it isn't very bad.