I think maybe it has, and each of us doesn't notice it when we're younger and we think that we're really arguing about principles. Before Trump Derangement Syndrome (Russia!) there was Obama Derangement Syndrome (Kenya!); before that there was Bush Derangement Syndrome; before that there was Clinton Derangement Syndrome; before that Reagan Derangement Syndrome (Oliver Sacks even included a bit in his book The Man Who Mistook His Wife for a Hat which alleged that there are people with a neurological condition which causes them to detect lies, who couldn't watch Mr. Reagan speak because everything he said was a lie; if true this would have been quite an amazing discovery …), and so on & so forth.
And of course a lot of this wasn't entirely unfounded. Mr. Obama really was the first anti-American president; Mr. Bush really was incompetent; Mr. Clinton really was a perjurer, philanderer, power-abuser & possible rapist; Mr. Reagan really did lie a lot (e.g. Iran-Contra); Mr. Carter really was incompetent; Mr. Nixon really was a crook; Mr. Johnson really was a crook &c. &c. &c.
The fact that we keep on electing compromised, power-hungry people to a position of extreme power is no doubt part of the problem, but even back when the presidency was far weaker you had the partisans of Jefferson & Adams maligning one another with language we would be shocked at today.
The only recent American president I can think of who was mostly decent was probably Gerald Ford, who never ran for the position. Maybe that's the secret.