This is actually a real problem more so in this case than most. There's an awful lot of satellites in low Earth orbit, altitude of a few hundred to several hundred kilometers. Atmospheric drag still exists here a little bit, and thus space junk will reenter and burn up in years or decades.

This satellite was in geostationary orbit, at an altitude of about 36,000 km. Debris up there can take hundreds of years to come down. Geostationary is a special altitude where the satellite orbits at exactly the same rate as the Earth spins. That means that a fixed dish on Earth will always point at the satellite without needing to move or track. So there's just one narrow orbital ring around the equator for that. That ring is not a place we want space junk to be, because if it gets too hazardous for satellites in GEO that basically removes our capability as a species to use fixed satellite dishes for anything. And that problem won't go away for centuries.

How did it break up? I wasn't aware that Boeing was determined to be a fault in the build process.