This baffles me as well. The childless woman would seem like a perfect dating partner for all the reasons you enumerate and more.

I suspect some men are confused by women who have reached their 40s not only childless but unmarried. I would even say there is some prejudice against still-single women, as if they must have issues related to men or to commitment or who knows what. Our culture is so family-focused, we don't know what to expect from a woman who has (for whatever reason) skipped that step on the expected path of life. (Or a man, though "bachelor" carries far less pejorative baggage than "old maid.")

I would also observe that children (or the lack thereof) are less on the minds of men in the older range of middle age, who are used to dating women whose children are grown up and moved out. I'll bet most of the ones who shy away from you are on the younger side.

Our culture of marriage and nuclear families is failing on so many fronts. A whole generation is rising now that has lost all faith in that plan and will soon be in your position, and we are being forced to develop new approaches to romance and pair bonding. Interesting times ahead!