Smart businesses know that when you've got a customer setup for recurring monthly billing, there's a certain percentage of these customers who will continue to pay even though they're not actively using the service. Part of it is laziness of figuring out how to cancel. Another part is the thought that they may someday use the service more than they are. This has been the model for gyms forever.
What Netflix did was force people to re-evaluate whether they truly were getting what they paid for, and in the process they added complexity to their branding by spinning off part of the service into a hard-to-spell company that had nothing buy a landing page.
While this may be good for today's stock price, I suspect many of Netflix's customers that re-evaluated their needs may not come back for quite a while ... if ever. There's more options available for media than there likely were when they first signed up for Netflix ... and if those competitors are smart, they'll target those customers to ensure they're aware of the alternatives.