And pirating stuff off Steam is generally extremely trivial, so it's a largely coercion-free business-customer relationship, and I think that's a large part of why they're doing so well. People like to support businesses that treat them well. And for those that don't? Well I think there's a reason that video game piracy is plummeting, while film/media/streaming piracy is surging.
Killing the secondary market for games hasten how soon they can sell $100 games.