Most satellites orbit higher than the ISS. If they didn’t they wouldn’t stay up very long. The ISS is only at 400 km up. That is pretty low. It would come down in about a year as shown below if NASA didn’t keep having it boosted. Other satellites, like Starlink for example, are higher so the orbital life at least matches its expected life. Starlink are at approximately 550 km. That gives them an expected life of about 15 years before they reenter the atmosphere and burn up.
The cause of the lifetime is that stray molecules of air collide with the satellite and gradually slow it down. Slowing it down means it drops just a little which only makes it worse. The number of stray molecules of air increases the lower you go. That is why it is kind of an exponential life versus altitude.
I would suggest that SpaceX is acting responsibly to assure they don’t leave space debris past the useful life of the craft. Satellites in geosynchronous orbit (35,786 km) may never come down.
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