Richard Todd replies to me:

>So there's a difference somewhere. What might it be?

One major difference is that it requires a lot more technical knowledge
to become a composer than it does a writer.  Another difference is that
musical scores for study have usually been harder to come by than books.
Amy Beach, for example, a fine composer who taught herself how to write
music in rural New Hampshire, had a devil of a time obtaining scores and
textbooks, although she came from a well-off family and could afford them.
For example, she did manage to buy a copy of Berlioz's Treatise on
Orchestration, but had to translate it from French before she could
actually study it.

Let's also ask ourselves how many women were admitted into composition
classes in conservatories.  Why was Amy Beach self-taught, when the far
less talented MacDowell received German academic training? I know that
as late as the 1960s, misogyny was pretty rampant in the composition
department I studied with.

Part of the reason this sounds so incredible might be that the stupidity
of otherwise intelligent males cannot, from our current perspective, be
readily believed.

Steve Schwartz