Space junk at that altitude does turn into debris, but it tends to deorbit on its own in around 5-10 years. The real danger is space junk that's at much higher

Space junk at that altitude does turn into debris, but it tends to deorbit on its own in around 5-10 years. The real danger is space junk that's at much higher altitudes. OneWeb and Telesat Lightspeed (in planning) operate at 1000+ km, where space junk will take 1000+ years to deorbit on its own. And OneWeb has already had a satellite failure where it can't deorbit the satellite.