On the other hand, geosynchronous satellites won’t ever clean themselves up and if control is lost on one, it’ll continue to be a problem for thousands of years

On the other hand, geosynchronous satellites won’t ever clean themselves up and if control is lost on one, it’ll continue to be a problem for thousands of years or until a retrieval craft is sent up. There’s not even really much of an opportunity to safely de-orbit if failure is anticipated because they’re so far out. With Starlink, in the worst case scenario dead satellites will be in orbit for 2-3 years, and if signs of giving out start showing up SpaceX can quickly and safely steer it to burn up, with a cheap (and likely updated) replacement being sent up within a month.