There's way too many resources that a woman can use to date(for example online dating) that makes it virtually impossible for them to be undatable. In online dating one woman is going to have dozens of men in her inbox regardless of her appearance.

This isn't the same for men, even average looking men will be lucky to have one woman reply to his messages. The only other route men have is to approach women(doesn't work most of the time unless you're good looking or rich) or hope to slowly build a relationship with a woman and not get friendzoned.