"Economies without property rights in capital" is a convoluted way of saying "economies without capital", and so of course those economies do not have to worry about any conflict between labor and capital, just as societies without higher education don't need to worry about SAT scores declining.

An example of such an economy IRL?

NK essentially operates this way, at least nominally.

Lots of small-community, low-tech societies (very much “pre-capitalist” in the view of either capitalist or Marxist teleogical economic descriptions).

Low tech societies still have capital. I was looking at givedirectly recipient stories, https://live.givedirectly.org/newsfeed/search?search=Kenya+C.... Almost everyone uses their money to invest in their home, livestock, or children's education. The push and pull between capital and labor absolutely exists here.

> Low tech societies still have capital. I was looking at givedirectly recipient stories,

I was referring to historical low tech, small community societies, not any places integrated enough with the modern global economic to have “givedirectly recipient stories”. But, that aside:

> Almost everyone uses their money to invest in their home, livestock, or children's education

Neither a home nor children's education is capital. Livestock is, but plenty of historical societies didn't feature private ownership of livestock (though it's probably one of the oldest forms of private capital.)

There aren't really any communities large enough to be considered societies and are so cut off from technology that they couldn't be the recipients of givedirectly. Homes and human capital are absolutely capital.