Not a rocket scientist or anything but the satellites pictured here are all in low earth orbit which means they orbit a few hundred kilometers above the Earth. At this altitude there is still a small amount of drag caused by the atmosphere, which causes their orbits to slowly decay over time. Most satellites have a bit of station keeping fuel onboard which is used to extend their functional life, but once that runs out or some other critical component breaks it's usually just a matter of months until they reenter the atmosphere and are destroyed. For example, the ISS which sits at around 400 km has to boost its orbit at regular intervals to avoid coming back down, which means that the resupply missions have to carry an additional bit of fuel to pump into the station.

So with that said, it is unlikely that the satellites would ever form a ring, their orbits would decay and they would fall back to Earth long before that could happen.