Yeah, you mention it, but I think you're vastly underestimating licensing costs. Hollywood / content producers have them over a barrel, especially now that they're spinning off the DVD business.
On top of that, those servers don't run themselves and those infrastructure costs you so quickly dismiss are significant.
This. When you own a DVD, you can rent it out as many times as you want and you don’t owe the studio another dime. When you have a digital movie on a server, every act of streaming it to a customer constitutes “copying”, subject to a license fee. And the studios want to milk that revenue source for all it’s worth and then some.
On top of that, those servers don't run themselves and those infrastructure costs you so quickly dismiss are significant.