Doesn't that only happen when the male line dies out? My fiancé is an only child, and she's taking my name, but she's got like 10 cousins with the same last name, most of them male, so the last name persists, just within her family, not counting the unrelated people with the same last name. Then you've got the small section of the population that renames themselves or is assigned a name independent of parent names.
So, it could happen, but I think given the variables involved, it's more likely that humanity will either die off or splinter into intergalactic colonies with widely differing norms, coupled with very sensual human-alien interbreeding, by candlelight, even with no atmosphere, while an adromedan Barry White soothes entry in the spiny yet inviting orifice with a comforting bass tone and light jazz orchestration, that leads to introduction of new sounds and forms of communicating identity with added, not reduced complexity.
