[Breaking Bad] is designed to take a guy from his beginning point to his end point and transform him from a good guy into a bad guy.
That's from Breaking Bad creator Vince Gilligan in a revealing interview in Grantland. I wish he hadn't come out so definitively with this thesis with the show still on air, but the quote does leave little doubt as to the course Gilligan is steering the show, and it's better than feeling like you're watching a show that's open-ended simply to maximize revenue from additional seasons (I won't name names, but everyone knows a few). It's a unique premise for an American television show, where even the darkest of protagonists in the past were intended to be sympathetic (Tony Soprano, Don Draper). Walter White's soul grows darker by the episode, making the show simultaneously more unique and yet harder to watch.
[possible minor spoiler ahead as I offer a general prediction for how the series will end]
Take the premise above and fuse it with Gilligan's statement that his personal belief system centers around karma, and it's not hard to imagine that Walter White and Jesse will meet with a tragic reckoning by series end (not that they haven't already suffered a huge toll already).
"I like to believe there is some comeuppance, that karma kicks in at some point, even if it takes years or decades to happen,” he went on. “My girlfriend says this great thing that’s become my philosophy as well. I want to believe there’s a heaven. But I can’t not believe there’s a hell." - Vince Gilligan
A natural question for Gilligan is whether a good man turned bad was the premise from the very beginning, and he offers not only an answer to that but names the moment he thinks White passed the point of no return, and it's not the one most would expect.
I think Walt reached the point of no return was actually before that, as early as Season 1, and it might have been the moment in which he was offered financial salvation. He was offered some sort of deus ex machina salvation in the form of his former partner coming to him and saying, "Listen, Walt, I've heard about your situation, and I'd love to give you a job, and I'd love to pay your bills, and I'd love to give you a free hand here." And Walt, out of pride, would rather cook crystal meth than take the help.
I was about as proud of that moment as I was of any we've had since, and I'll tell you why: My first inclination for this show was that this was a good man — fundamentally good — who was doing a really stupid thing, cooking crystal meth, and was ignorant of how terrible this world was and would quickly be in over his head, and quickly forces beyond his control would make him continue cooking. Perhaps he'd be held in some sort of bondage by some kingpin and made to cook meth. It occurred to us early on, "You know what? We don't want to see that. No one wants to see that.” They want to see this guy, right or wrong, have the will to go forward in this thing. That's a much more interesting character than a character who is forced simply by dire straits.
Last season, the show's third, Breaking Bad was the best show on television, with at least two of the most memorable episodes of TV, and if people argue it's the best show on TV, or the GOAT, I don't blink.