You can turn that around - why didn't 19th century painters use 20th century styles?
Art evolved in relation to the social and historical circumstances. At the very least you would need to give all the context of the 20th century beforehand (except for the art itself).
Art evolved in relation to the social and historical circumstances. At the very least you would need to give all the context of the 20th century beforehand (except for the art itself).