I've recently acquired some copies of Cycling magazine from the early '30s, and they discuss precisely this question; why do few women cycle? Their answer in a touring context seems to come down mostly to parental anxieties, particularly mothers'. Though at the same time, women are almost completely absent from these magazines. Mentioned in the very occasional race report, in articles by the contributor "Femina" (not weekly though, unlike "Wayfarer", F.T. Bidlake and various others) and once in a quote from Galsworthy's latest novel, but never in random articles. Every non-specific cyclist is a he, "the rider who looks after his machine will... " etc, and all the fiction* features 100% male characters; which is all pretty standard for the time, I suppose.
*Yes! Fiction in a cycling magazine. Mostly stories about bizarre events at club Christmas meets.