It's like airplanes. You can't prove they can fly to someone whose mind is not able to cope with the possibility.
However, it is so simple to confirm that the ISS orbits the Earth at 5 miles per second (and has done so for 20 years) that it is pathological not to accept such a simple fact. Of course, understanding this makes it not so surprising that there are thousands of other satellites.
It is of course absurd to believe that 44 countries have spent billions of dollars pretending to launch satellites. The simpler truth is that some people are just, to be blunt, too stupid to accept the fact. [This is not a rash conclusion - it is reached after them ignoring all of the evidence repeatedly].
Can anyone prove they have 1000's of satellites in so-called outer space? And please don't post a link to a plethora of NASA cartoon animations of satellites