Radiation hardening is a big issue. Commercial components could fail due to ionizing radiation, at a high enough rate that it puts the mission at risk. Also just genera design. Robots that can be easily repaired and recharged have different design parameters than those that have to go to Mars.
True, it won't be easy, but better than sending people there. Spend some billions and in 10 years bring some robots, and explore the planet without risking any human life.