I get the impression that it wasn't that those powerful people paid to have sex with kids but rather that Epstein befriended them and took them to the island and provided them with sex with kids and he documented it in some way and then he had blackmail material over powerful people. And then at that point he could get money or whatever he wanted from those people. Which goes along well with them later offing him in jail so he could never squeal or reveal the blackmail material.
I've heard it conjectured that Epstein was with US intelligence or possibly intelligence from some other country and it was an intelligence services way of leveraging their power over powerful people in society. That also goes along well with him latter getting offed in jail.