Priests will celebrate Mass everyday even if the lay people are not present. One of the priests that I know, has only 2 days in 50 years as a priest that he hadn’t celebrated Mass or gone to Mass. Those two days he was in a hospital and wasn’t allowed to eat or drink.
I am looking forward to the Rorate Mass in my parish, but due to the pandemic, the priest might have to celebrate Mass by himself without any faithful present, if there is more and faster virus spread in the area.