What do you think of people that end a family line?

I have one friend who is the families only son, he has two sisters. He made a decision as a young man to never have kids, and he found a wife that shared that view. Now he is an old man. His sisters married and changed their names, so his blood name is coming to an end when he dies.

Another friend, the only boy, also has two sisters, living with a woman, they had two kids together, but they never married, the wife runs the show in their family and gave both kids her last name, so he changed his name to match hers. The two sisters married and changed their names, so once again the family name dies.

What do you think of people like this? How many generations did they abandon.