Quote from the article
"But like many other solar-powered craft on Mars, InSight's limiting factor was dust choking off sunlight, which is the main source of power for the mission. NASA has been warning for months that the InSight Mars lander would likely to fail by mid-year
2022, even after granting InSight an extension for its continued science value.
Due to weight and power concerns, the lander did not carry a supplemental system to clean off dust, such as motors or brushes."
As the article says, dust accumulation on the solar panels is a restricting and eventually terminal condition for solar powered craft on Mars. If a light weight solar panel cleaning system could be designed it would be a great benefit. If not a motorised brush/wiper system then possibly a compressed gas system to blow the dust off?