It is somewhat astounding that Mercer/CA were able to attain so much political influence -- by following the data collected and providing a candidate that was anti-establishment. Quote from Mercer:
“America is finally fed up and disgusted with its political elite. Trump is channeling this disgust, and those among the political elite who quake before the boombox of media blather do not appreciate the apocalyptic choice that America faces on Nov. 8.”
In a political domain in which a large portion of the population is disenchanted, it's relative, possibly frighteningly, easy to preach a simple and easily digested and accepted message of salvation. It is almost always false. It is hugely appealing.
Trump has tapped that nerve, with the help of a number of others, the Mercers among them. I'd add Thiel to the list also.