One has to take a contrarian view of one's own anxieties: this is all good for the republic, because it snaps people out of their complacency.
Complacency is what gave us Trump in the first place. The "it'll never happen" attitude pretty much guarantees that at some point someone will purposely or accidentally benefit from it. Now that the cat is out of the bag people are very focused on the issue at hand, which is good.
To believe America will "fall" you have to believe that there is, or there soon could be, a majority of people who believe in dismantling democracy and abandoning the constitution. If that is the case then America has already fallen.
no, it's not just complacency. In the 2016 vote, he did get a lot of the popular votes (even tho hilary got more). That's a sign that a lot of people in the US do agree with his world view - whether they understand that it's just retoric trump is throwing to get votes, or they do truly feel it, is moot.
Trump _only_ got into power because there's enough people in the USA to get him into power. This isn't a case of a one time bad president - it's the psyche of a nation.