[root_axis]

HBO seems to be able to consistently churn out hits, and not just "hits" but cultural touchtones that ripple throughout pop-culture.

[JadoJodo]

But they also have a history of original programming that dates back to the early 90s (and earlier). They've had time to perfect those ripples.

[mkl]

Even their first original show Oz (1997) [1] was good. It was clearly experimental and low budget (it's set almost entirely inside a prison so needs very few sets, props, costumes, etc.), but designed around that limitation to focus on the writing and characters. Netflix tried a similar strategy with one of their first original series, Orange Is The New Black.

[1] https://en.wikipedia.org/wiki/Oz_(TV_series)

[dhosek]

More accurately, their first one-hour drama. They produced original content as early as 1976, not including sports programming or comedy showcases.