That wasn't the case for AMC before "Mad Men". Now, in addition to "Mad Men", they have "The Walking Dead", "Breaking Bad" and "Hell on Wheels". Even more than that, they have my guarantee that I will at least try a few episodes of any AMC original show that comes out.
You're right that Netflix would have to build an audience, but if they are able to create exceptional quality shows, as HBO and AMC have done, then they can very print that certificate very quickly (within a couple of years).
