[ClumsyPilot]

I am no expert, but I can imagine there are many kinds of laboratory equipment that is way too heavy to pit on a rover, perhaps mass spectrometers, etc.

Biological wxperiments is a big one. There is kind of outstanding question of perclorates in martian soil and its toxicity to earth organisms, plants, etc.

[ta8594505930]

The mars rover does have a spectrometer. It's called ChemCam [1], it uses a laser to vaporize a small amount of matter and them captures the spectrographs of the resulting plasma with a camera. That doesn't take away from your point, but it is a cool piece of equipment.

[1] https://mars.nasa.gov/msl/spacecraft/instruments/chemcam/