You make very good point that I have no argument with. It's true that there were "bad" politicians way before 1991. It's also probably true that Trump would have never won if it wasn't for a lot of things aligning in a way that set him up for the presidency.

However, The media tends to focus on the scandalous and the simplistic. It's all true but what really contributed to Trump's rise in the polls to the point that he could even be considered a political candidate was not Russian ad campaigns on Facebook, the FBI, or the Supreme Court. It was growing public opinion that supported his claims that a change was necessary in Washington DC. Manay American found that message to resonate with their own beliefs, especially when made by an "outsider".

Also, consider that he still beat all of the other Republican candidates. That says something. He still got millions of Americans to vote for him and that says something too.

It's also similar to what is happening in Europe, which I think is rooted in a general lack of confidence that the public has for their politicians.

A recent survey by The PEW, found that public trust in the government remains near historic lows. Only 18% of Americans today say they can trust the government in Washington to do what is right “just about always” (3%) or “most of the time” (15%).

While you may be right that, if we judge on merit, the politicians of old were no better than the politicians of new and vice versa. But, in the court of public perception there is a shift that is hard to ignore.