IMO, there are three major factors in this move, none insignificant:
* US new cases numbers have plummeted since January 8th;
* Trump is out of office;
* Dems know that continuing the shut-downs and Mask-Mandates much longer will result in mass push-back, in resistance and in 2021 and 2022 ballot boxes.
Were the new cases plummet the sole factor, this Mask-Mandate and shut-downs lift could have been done 2 months ago, plus-or-minus Michigan and New York.