First off, I don't understand comparing XBL to Steam...They are different services altogether.
Secondly, you pay for an overall better system. XBL has more games, better games, and vastly more content. Microsoft has usually been first when it comes to some sort of new integration like Netflix OnDemand (which is beastly).
Gold members also get better deals on some games, which subsidizes some of the costs of the service.
Ultimately, the service is built on the back of the revenue that gold earns. Although it can be frustrating that so many things (like online MP) require gold, the fact is that silver members still get access to tons of extra content that PSN cannot touch, and Wii doesn't have.
Why do you think that both Sony and Nintendo have hinted they may charge for their services? The fact is, its a good business model, and even the free companies realize that they are getting hurt where MS is making its mark.
Back from the dead, I'm afraid.
