Trump will continue to stay in power until either

1) The economy tanks
2) We suffer a humiliating military defeat

And either of these must occur far enough into the future that neither
Hillary, Obama, nor the Establishment/Deep State can be blamed for it.

Remember, a US legislature which can simply refuse to hold hearings for a Supreme Court Justice is not that far removed from one that can simply refuse to honor a Supreme Court decision.

Trump has promised his constituents prosperity and military victories and a restoration of 1950s culture and values; and his party, massive corporate tax cuts and a regulation-free business environment. As long as it even looks like he is delivering, he is safe.

As far as the "epistemic crisis" is concerned, we've been there before. Nazi Germany, Stalin's USSR, Mao's Cultural Revolution. I am surprised you are as surprised as you are.