I don't deny that Republicans existed before Trump, but Trump being elected certainly fast-tracked this skyrocketing fascist disaster.
I think it's like that old saying about bankruptcy - it happens very slowly, then all at once
The rise of right-wing propaganda mass media has been simmering brains for 3 decades in a populist, grievance and resentment stew and positioned things perfectly for right-wing propaganda to explode in the internet age - once social media came around, it was a renaissance for the paranoid-style radical right-wing demagogues, and they exploded in numbers and reach. In turn, that tilled the soil for a Trump figure to come along to disrupt things.
Trump basically took all the recurring themes of grievance from right-wing media to the extreme to turbo-charge the anxiety and fear of the right, including most things that were generally considered wrong for politicians to say/do.
It's almost hard to remember the before-times, but Trump was the first modern presidential ticket that outright attacks the media (calling them the enemy of the people, fake news, etc) to de-legitimize them - it used to be a point of pride in this country that politicians didn't do stuff like this, because it's a feature of authoritarian regimes, not democracies. Right-wing audiences were very used to hearing that sort of thing though, because it was a common feature of the right-wing propaganda media they had been boiling in for years.
Sure, absolutely. But again, the people voted for fascism. At his pre-election rallies he'd say shit like "I'm gonna be a dictator for a day!" and get cheers.
An America that didn't like fascism would have never even let this man win the primary.