With at least 10 million Xbox Live Gold subscribers, they might be right. You already have an audience that doesn't mind paying for online services and makes use of their console on the Internet often enough. In addition, you have the unknown number of Xbox Live Silver subscribers, who might see the addition of Netflix functionality to be all the motivation they need to subscribe. All in all, the estimate is that Netflix might gain an additional 1 million customers, making the 360 trounce even their own Roku for streaming subscribers.
Now, if only Netflix can solve the issue of having nowhere near the streaming selection that their standard DVD library boasts. For all of you Xbox 360 users out there, have you made use of the Netflix streaming service on it, or would you if the selection was better?