A few different trends feed into the Trump phenomenon.
One of the primary characteristics of digital media (1994 - ? ) is that the "official" position is no longer the official position.
The Law of Large Numbers and Second Law of Thermodynamics both make the unlikely more likely.
There is also a general trend toward greater rights for an ever-greater share of persons, dating from approx. the Elizabethan era. This led to greater autonomy of the merchant class, the English colonists to the New World, to suffrage for unlanded males, etc. Perhaps the seeds were in place before E.'s defiance of the papal bull; but the general trend is undeniable.
I see a realignment of the parties.
As far as I can tell, the realignment favors the Right, generally.