Why can't any other satellites be seen from the ISS live feed?

First, the ISS orbits the Earth at altitude of about 225 miles. The live feed camera is pointing down at the Earth. Most of the satellite orbits are far higher than ISS.

Second, the live feed camera points at a very bright object, so the camera's aperture is set accordingly. You will need a much wider aperture and much longer exposure time to capture a tiny, dim object such as a satellite.

Third, even the largest satellites are only about 40 feet across with all of their solar arrays and antennae fully deployed. These satellites orbit the Earth at over 23,000 miles. At that distance trying to see a satellite is like standing in one end zone and trying to spot a speck of dust on the goal post at the opposite end of the field.

The ISS shares about one trillion cubic miles with about 1000 smaller satellites, so a billion cubic miles has about one medium size satellite. The field of view at any second only contains about 1000 cubic miles likely to have a midsize satellite, so you should see another satellite about once per million seconds. How many large air planes have you seen in Earth's atmosphere on the live feed? The largest airplanes would be a tiny speck, that would show as one pixtal rarely, I think. Most space junk more than a mile from the camera would be too small to be seen.

With thousands of satellites in orbit, the average distance between them is over 225 km. When you look at the actual orbits, there a very few that come that close to the ISS, at any time.

The live feed from the ISS doesn't have much (if any) magnification. So it's very rare to see a 10-meter object (or smaller), 200 km or more away, moving at a relative speed of 10,000 km/hr or faster. The ISS is moved about once a year to avoid small bits of space junk coming within 25 km.

Becasue, to avoid a colliuosn that would destroy both the ISS and ther satellite, the ISS cam ber STYEERED away from other satelloites. The distance is large enough, and the satellites are small enough, thet they are too far awsy to bee seen.

If you take a look at some of those timelapse videos of the ISS showing the Earth below... If you watch the background you can see many satellites zip past.

For example in this film you can see several satellites, including two at once in at least once sequence.

https://youtu.be/2dAHGvmT6v8

Too far away, and too small. Even the bits of space debris that the ISS is moved to avoid collision whizzes by so fast as to be unseen.

Too small

In a higher orbit

In a different orbital plane

Space is big, satellites are not.