The runaway success of Game of Thrones was hardly assured, considering it's spiritual predecessor, Rome, got nixed due to high budgets and middling ratings. But Game of Thrones has become the most popular show of all time, averaging over 10 million viewers per episode just in live US views, an insane feat for a program on a premium cable network. It has further become so embedded in the cultural zeitgeist that non fans are being rounded up and shipped off to the Iron Islands so Thronies don't have to explain...
I usually call it documentary-style TV because 'reality tv' can leave such a bad taste in peoples mouths. And it shouldn't. There isn't anything wrong with reality as a format. Sure, there is a good deal of trashy TV in reality, but that's not the fault of the format; there is some level of trash in every format that exists. And hell, science and nature shows fall into doc-style TV- the only difference between those and other reality programming is that they're about concepts and wildlife rather than people. But that's not to say...
"A story should have a beginning, a middle and an end, but not necessarily in that order."-Jean-Luc Godard...