While the ore other factors that make Lunar observation satellites harder to do and more expensive (harder to communicate with due to distance, different thermal environment, no protection from radiation by the Van Allen belts, etc.) one big issue is that low Lunar orbit is by default unstable:

https://en.wikipedia.org/wiki/Lunar_orbit#Perturbation_effec...

Basically the gravitational field of the Moon is "lumpy", resulting in deceleration of low orbiting bodies as they are pulled around in orbit, until they crash into the surface.

There might still be dead probes from the 1960s/1970s orbiting Mars, but there are no inactive spacecraft orbiting around the Moon. There are now some specific orbits known that you can place a spacecraft in to reduce the effects but I don't think even that works to 100% percent efficiency & thing will still go down quite quickly of you loose control and can't do course corrections.