Full question was "When they got to be queen, why didn't Elizabeth and Mary do anything to upgrade their mothers' resting places (i.e., move their bodies to Westminster Abbey)? In the 1900s, Queen Mary, wife of George V, provided Katharine's grave with a beautiful acknowledgement of Katharine's queenship; why didn't Katharine's own daughter do that for her? Same for Elizabeth?"

I think that Elizabeth was aware that she had many challenges to her throne and that mentioning Anne Boleyn, who was still unpopular with many, would be dangerous, never mind moving her grave. Anne Boleyn was still seen as a traitor who deserved to be buried like one.
As far as Catherine was concerned, she was buried in Peterborough Abbey (now Cathedral) as Princess Dowager, not Queen. Yes, her grave was "upgraded" by Mary of Teck who marked it as the grave of a Queen of England. The cathedral hold a special service annually in her memory.
I'm not sure why Mary did not move her mother's grave, perhaps she felt it was best to leave her mother in peace.