When they tried to move beyond DVD's their plan depended on becoming the single source from which you could get any content you wanted streamed instantly. They built an infrastructure unrivaled by any competitor at the time to accomplish that. But in the end they couldn't unravel the knot of shifting license agreements and availability windows that curse the streaming industry. Instead of opening up the licenses the big content creators eventually started their own streaming services, and as a result you never know what will be available when or for how long. That's simply not a premium service, no matter how hard they try.
Their original DVD business has contracted a lot but remains solid with a constant core of users who either don't have good enough internet to stream or don't like the availability problem. While some new stuff isn't being released on DVD anything before 2015 or so is always available because once they're pressed DVD's are physical objects subject to the doctrine of first sale, and Netflix can rent them to anybody they want whenever they want until the DVD breaks in half. I don't watch a lot of TV so the 8 discs or so I get per month are well worth the cost of the 2 disc out at a time plan.
Unfortunately, the promise of streaming is being ruined by a problem which is not technological, but legal. Until there is something like a universal permanent license that most of the content creators will agree to so all the content is available from one source all of the time, streaming is going to be a minefield of shifting availability and service consumption. And being at the vanguard of that failure has not been a good thing for Netflix.