Yeah I'm not qualified to say precisely why things are they way they are. But I also don't understand how people can look at such a statistic and decide that mathematics teaching cannot contain any inequality based on some high-minded, Russell-esque argument.

> If kids from disadvantaged backgrounds are not shown how beautiful and useful math can be, what motivation would we expect there to be that could carry them far enough in the subject to get a phd in it?

Right, and the current homogenized curriculum is not great at inspiring very large swaths of the population. It is pretty good at 1) letting people not very interested in mathematics become teachers of mathematics and 2) lining textbook publisher's pockets.