Mars rovers are expensive as fuck, their capabilities are basic at most when compared to humans, and even then they aren’t built to withstand snow and ice. Research institutes don’t send people to the ass end of the world just because they can.
Remote sensing is great, but a considerable portion of the work done in the Antarctic is to benchmark the data we get from Earth observation satellites so we can develop those capabilities further. And even then, there’s only so much that can be done with satellites.
They sure don’t tend to do that, but there are still mundane explanations for this. An unintentional collision between the satellite and another object being one of them.