@Edent Maybe it's also a question of age. When we got Internet access in the early 2000ies, my mom set up a family mail account everyone in the family used. I made my own as an older teen for privacy reasons. When I moved in with my partner, we both already had our own bank accounts, email addresses and stuff and the thought to give either up on the autonomy or creating something joined never even occurred. Emails go to the person who pays for the thing/does the main organising.