Earlier quoted context omitted.
But what's stopping Netflix from replicating this success? To what extent is the success of HBO purely a function of the capital they invest? i.e. what non-financial assets does HBO provide that contribute to the success of its shows? What does HBO bring to the table that Netflix can't?
HBO is already a premium brand, Netflix is not. Although nothing is stopping from Netflix from becoming one, getting over that hump is not easy.
HBO has a quality seal of approval that has taken 15 years to cultivate. That can't be bought or earned overnight from one show. HBO consistently gets more Emmy nominations than every other network -- once Netflix is able to counter in that area, then it will happen.
Still, getting over the hump can happen. Look at AMC. Before Mad Men and The Walking Dead, they were best known for the terrible original series Remember WENN (don't ask, it sucked and I was in 7th grade when it premiered). Now it's easily one of the best networks on TV. Same for FX. Justified, Always Sunny, Sons of Anarchy, Archer, The Americans are all fantastic and this was a brand that was best-known for playing Fox reruns until about 7 years ago.