1. Misty signed a contract with Alex and Anna to do what she's doing now. If she decides not to do it anymore (good for her), then she will not be paid anymore. And she's paid on %. The more viewers she has, the more money she gets. That is why she invites guys everyday. It's not just because she likes what she's doing, but also because she wants to earn more money.
2. May be i misunderstood you but what do you mean by: "If Misty has no emotional attachment to any of these guys that she fucks I don't know why she doesn't try to pass some of the better ones off to Lisa."