The answer to how Trump has succeeded is really simple: He lies nonstop, and lying works. Sure, there are other factors in play—he tapped into and intensified a certain strain of profound proletarian resentment of liberal elites, and … well, that’s about it. But mostly, it’s the lies.
…And, to reiterate, Trump tells many such lies a day. He talks to the press two or three times a day most days, which probably adds up to what, 45 minutes, an hour? Spitballing it at one lie every two minutes, which may well be low, that’s around 25 factual lies a day.
Indeed, tis a cute jest about Confirmation Bias, which is fair in polling given the challenge it is.
Just a note that Real clear politics, the owner of realclearpolling.com was considered nonpartisan until a few years when more conservative influences have taken root. I point it out in contrast to Nate Silver who tends to lean left a bit.