Do you think it’s possible he’s not part of it?
Their usual SOP tends to be that they approach anyone very successful and 'invite' them to join them. Failing that, they offer to buy the originator out. Failing that, they threaten to kill them and ALL their extended family.
As it was, IBM MADE Gates super wealthy seemingly by choice. That frequently seems to be the case ... some decision is made in a lofty smokey room and it's a done deal.