My honest opinion: previous Presidents (mostly) willingly followed the rules. This President thought, "I wonder what would happen to me if I didn't follow the rules". And the answer seems to be "Nothing".
If anything's changed, I think it's a kind of "democratisation" of opinion. For example, the Washington Post was essentially able, though investigative reporting, to impeach a President. I don't think the same thing would happen now because the idea that "something must be done" used to come from those same media outlets. There was a more focused opinion driven by a few players. Now opinion can be swayed by anyone with a Twitter account (or access to Facebook data, it seems). Several people opined that Trump would not make it through his first term without getting impeached and I think he's shown that he has the ability to dilute public opinion. There have been several points in his first term where I think a President would have been devastated by public opinion had they tried the same thing in the past. He's had relatively no trouble navigating the issues. I think there is just no way to unify the chaos that is public opinion these days.
And I will say, although I'm not a fan of Trump's policies (or actions), he's pretty darn good at surfing that chaos -- and stirring the pot so that the chaos continues. If you want to put a different kind of President in power in the next election you're going to have to pick someone who can diffuse that chaos and create a clear, powerful and unified message that the average person is going to identify with. I suspect it will be incredibly difficult.