Not impressed by a 1-2 MP camera? Well: it was tested and developed for about 5 years before getting on the rover, which means it didn't get further in the chip development road.
Industry graded cameras are still in the VGA-5 MP range. Check out companies like ISVI, AVT, PointGrey, Basler. Only specialized companies offer sensors like 29MP full frame chips. The grunt work is done in low megapixels.