I mean, there are some people you'd prefer to befriend/date/marry over others, right?. your criteria is probably not just money; you might care about physical characteristics, intelligence, character, etc. to the extent your criteria overlaps with others', something like a market emerges, though the prices are not denominated in dollars. "value" is kind of a crude word to use, but it's a useful abstraction to answer the question of why some people have very many options in friends/partners and some have very few.