In Likutay Nanach I posit that in the times of the Bal Shem Tov the hanhaga (Divine Rule and Conducting of the world) was set to the mode of Soaf (-as the Ramchal revealed, that HY is One, the very same One before and after and during the creation of the universe. With the creation of the universe there is the creation of beginning and end, and the beginning is G-d's unity as it stands, and the end is G-d's unity as it is reflected from the entire experience that was the universe, ultimately both of these are also One, however in the time of the universe, there are two approaches to reveal the unity, either in one shot to introduce the beginning, or to have to go through the whole rigamarole of the universe, until everything is rectified to reflect the unity of HY) – and that is probably why it was in those times that the advent of surname. Because the Roash is the aspect of the male, and the Soaf the aspect of the female, and in the mode of the Soaf, the Soaf has to reveal in itself the Roash. So as long as the hanhaga was still open to have the Roash prevail by itself, there was no special association given to woman's role, a marriage was primarily just the man's completion. However once the mode of the Soaf became necessary, the woman's role in the marriage became the anchor, and thus a real family indigenous to these two people was created, ultimately following the surname of the male, because the Soaf reveals the Roash, but here the woman has full equal representation in that LAST name.
Na Nach Nachma Nachman MeUman!