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.

Most high resolution "satellite" imagery on Google Maps etc is actually stitched from photographs taken from cameras attached to small aeroplanes which fly at a low altitude even compared to commercial flights let alone 100km.

There are a few high resolution satellites but there frame is very small and not suited for complete coverage. If they are geostationary they cant look anywhere, or they have to look at an angle giving oblique photos. If they are moving then they are only over the part of the earth once per several days (weeks/months?)

So while these images of the landers are from a satellite orbiting the moon, the satellite is orbiting with an eccentric polar orbit, and the images it takes may be perfect for it's mission but might not be good enough to identify small 1960's landers.

> that's from over 100 km up through an atmosphere

Could be from atmospheric fly-overs.