I’m sure the cost-benefit analysis was done. Wind has helped clear dust off the panels on Insight and other landers, but didn’t enough in this case. The environment is unpredictable and the mass and complexity they can carry is limited. Something to tilt, brush, repel, or otherwise remove dust could have failed and ended the mission early. Or it could have succeeded and we would have had fewer instruments for longer.

The only way to get more resolution would be to make the camera lenses larger (or add more of them) just due to the wave nature of light.

Interestingly, phone cameras are already nearing the physical limits of how good they can be. With a certain aperture. You can only resolve details of a certain size, even with infinite pixels. There’s definitely some funky stuff with including more cameras, but you notice the megapixels on phone cameras haven’t increased much because that’s not the limiting factor

It never moved, it isn’t a rover. It’s solar panels are stationary too.

While there are other methods of getting dust off, Martian dust is fine and sharp enough, having not been eroded by water, that it would scratch the solar panels as it was scraped off.