If you remember Blockbuster - there were tons of old movies, and yet the real business model was in providing the new.
Netflix started off with providing the old, and has quickly shifted towards providing the new, including creating a bunch of it themselves.
I think the real longterm move for Netflix is to incorporate RottenTomatoes and IMBD into their business.
There is simply too much stuff, and if you can't compete on providing content that's been advertised somewhere else as 'good' (what Disney/Hollywood blockbusters do), then you need to do that yourself.
The way to do that is through the people, the only real cost will be in moderating it.
I shouldn't have to randomly watch 20 minutes of random series to see if I like it - Netflix is going to need to be in the business of providing intelligent suggestions, while educating the casual viewer on who's up and coming etc. You know, internet forums reinvented.
My 2 cents :)