You know even the bible says, a good wife is hard to find, I say this in the assumption that your definition of good is of the same nature as that of the scripture.
But when it comes to the reason why good women are unmarried, I think there's more than them being locked in the house. Today's men's mindset is a huge problem in the society than the availability of good women. Majority of men say one thing but they mean another. For example most men cherish a good mannered woman in their words only, in the doing the go for woman whose behind is...... You know already. They put the emphasis on look more than the being, on the form than the function. Look at cosmetics, look at the fashion and style and look at the plastic surgery women go for, you will get the idea of what image their after and they want this image for who to see.
However not all women go for what I have described but trend is growing at a terrific speed. So sometimes see a good women you need a good mindset. May be good women are unmarried because most men have a marred mindset, which cannot see good.

chalcedony this is a good article which can provoke spirit debate, thank you.