If even 1% of Starlink satellites crap out before their planned EOL, there could be hundreds or thousands of them left in orbit for hundreds of years after the constellation is inactive
No way. Orbital decay times increase more or less exponentially, and once you get above the thermopause (which moves around from 500-1000km based upon terrestrial and space weather conditions), atmospheric drag becomes practically 0.
SpaceX is upfront about this in their FCC filings:
"The natural orbital decay of a satellite at 1,150 km requires hundreds of years to enter the Earth’s atmosphere"
All current satellites are in 550 km orbits. They had plans to also launch in 1150 km orbits but they made some FCC filings requesting to reduce the altitude.
On April SpaceX modified the architecture and submitted application to FCC proposing to operate more satellites in lower orbits. Previously they had approval to operate almost 3000 satellites in orbits between 1110-1300 km. Now the modified plan foresees 1500 satellites at altitudes between 540-570 km and another 7500 satellites in orbits around 345 km at later stages.
