Women working in the professional marketplace keep their maiden names for economic reasons.
Another reason is to provide privacy for the children and family. I can see why some women attorneys, famous entertainers, or those who have significant press coverage, might want to their children's names to be different from their public name.
Here's another reason.
The husband of my children's pediatrician died in his early thirties. She used his last name and the entire town knew her by her husband's name. (She likely had several thousand children in her practice). About 15 years later she remarried and again changed her name. Do you think anyone in the town accepted this new name? NO! She was always known by her dead first husband's name.
In my case, I simply did not mind if people, in private settings, called me by my husband's last name. It was not a big deal to me, but legally changing it absolutely would have been a big deal. Once a professional practice is established and a network of professional contacts is made, it is economic idiocy to change one’s name.
By the way, my children have their father's last name.