The worry with the self cleaning band is the possibility of Kessler syndrome. See, the geosynchronous satellites are basically stationary relative to each other, and geosync is huge, so if one is junk, it's stationary junk with nothing around it.

LEO orbits, in the other hand, criss-cross each other in a maddening dance. And if one shatters into dozens of tiny projectiles, that could shatter another and another into a cascade of space shrapnel. And then low Earth orbit is closed. No starlink, no iss, no manned spacecraft, etc.

It would self clean in a few decades. Three. Maybe five.