Alternatives have been developed by well-meaning groups, but adoption has been slow, in part because many designers have simply failed to consult the actual women for whom they are designing.
This reminds me of public toilets in urban construction. It is not hard to find that the number of men's and women's toilets is the same in almost all cities. Because most urban designers/planners in cities are men, they don't need or take into account that women have menstrual problems and may take longer to go to the bathroom, which is why there is always a line in the women's room and an empty men's room.