Netflix costs between $7-$12 per month. Many of those subscribers will not last the whole year. It is awesome they are spending basically 100% of their revenue on new content, but this model is not sustainable.
If on average you're getting ~$10/user/month, that's $120/user/year of which you're just spending $70/user/year, and thus have gross profits of ~$50/user/year. In other words, you're getting $12B in revenue, $7B of which you're spending on content to ensure that churn stays low and people continue to re-subscribe.
While their US rates may be $7-$12 per subscriber, their international revenue projections may be quite different. For example at current exchange rates I'm paying just under $15 USD for my account in Australia(though I'm sure not every country is so expensive).