You introduce somebody to your attractive single friend there's a real chance they hit it off and form a relationship. You introduce them to 100 attractive friends, one makes more money, one has a more stable job, one is flirtier, etc then it's both exhausting and none of them seem like a great opportunity.
I think there are certain basic psychological facts that are anti-standard-economics that nerds (and therefore tech companies) almost always tend to be completely blind to. This is one of them.