We didn't stop creating last names. E.g.

• people that migrate from Germany to the US still often translate their last names - which creates new last names.
• Nordic countries create new last names with the -son suffix. With the still standing creativity in first names and immigration from other countries this is a never ending source of new last names
• Eastern Europe sometimes have gendered last names (Zelenskys wife is called Zelenska) which might become new last names when people migrate there or out of there