HAS Realism supplanted Pragmatism in American thought.
Otherwise stated, has blind faith pushed facts off the board.
I'm a little confused by your phrasing. "Realism" seems to me to be the opposite of "blind faith."
But if I guess that what you are asking, is if there has been a fundamental
philosophical change in America, I would answer "absolutely not."
From my historian's viewpoint, I've seen no general change in American philosophy in two hundred years. Mainly, because American Philosophy isn't really a thing, in and of itself. It's like American Society: American Philosophy is the vague, foggy resulting sum of the individual points of view of three hundred million individuals.
What I would support, that you might be referring to, is that we have had a fairly recent shift in what could be called political manipulation technique, away from the use of factual investigation and logical deduction, towards making important political choices based on emotional fits of pique, and your blind faith. This is the unfortunate but to be expected result of decades of encouraging voters to refuse to believe anything opponents say, even when it is supported by various authorities, and to vote instead, based on who they are upset with.