In the world in Dragonball, what drove the earthlings to phase out the use of family names?

Perhaps Dragon Ball’s earth is set in a future where people have realised marriage is an unnecessary social construct, and a person shouldn’t be judged or exalted based on family ties.

What @Seek said… Which I actually might start advocating for. I was thinking something similar to what she said, but the way she explained it… Now I find myself compelled to seek out that sort of egalitarian society.

I do not remember there being any indication that people have stopped getting married.

But @ragingloli… Did you see an indication that they continued getting married? Long-term relationships don’t always equate to marriage.

I have a DB dictionary, just skimmed through the section about humans, their culture and all, and I’ve not seen an explanation for this. I will read it thoroughly later, but here are some interesting points to consider, which may, or not relate to that.

The whole world, on earth, although divided by “provinces”, is basically one nation, ruled by one king. I remember that from the sections in the manga when Kakarot was a kid. As well, the Christian god is stated to not exist in this universe. (although there is a “god”, who, as far as I recall only Kakarot and some of his friends met directly)
No Christian god, one nation, could play on last names. Personally I do not really believe, in this world, that relationships have much of anything to do with last names, or their lack.

Also, racial discrimination does not exist in this world. Racism is not a thing. Not sure if that can be related. (although the Saiyans do perceive themselves as superior)