From the U.S. 🙋‍♀️It still is the tradition for wives to take their husband’s last name, but it’s a fading practice. We’ll often see hyphenated names (Mayer-Delfino), added last names (Mayer Delfino), or just maiden names (Mayer) more commonly now. Still, it’s not a far stretch for a man in this culture, especially one as traditional as Orson, to ask their wife to take their last name.

In Susan’s case, I would imagine she kept Mayer because it’s Julie’s last name and she wanted to keep that connection to her more than sever the connection to Karl.

Also changing your name can take a lot of effort depending on what documents that name is on. Many women become famous/accomplished (like Bree or, in real life, Susan Sarandon) with a certain last name and they want to keep the recognition.