>>5963479well I can say the same thing about asian art, if the painting needs to be justified by saying "it's good because it has pretty anime girls" then it's shitty
but you need to take in consideration that they did not have the resources we have today, not even pens and markers, not to mention a whole bunch of references you can find on pinterest
and IMO, these works look no worse than modern western and asian artists, and in many aspects (such as color, shading and composition) are even better