[alden5]

Starlink satellites only last about 5 years before they run out of gas and are decommissioned with an end of life maneuver which sets them on course to burn up in the earth's atmosphere. I doubt many others besides maybe amazon will want to launch satellites at the same height as spacex's, especially considering how insanely expensive and complicated launching something like the starlink network is. Another point to consider is how small they are compared to the area they occupy, they have plenty of room to spread out and they're constantly monitored to calculate the probability that they might collide.