If Trump survives a full 4 year term -
He will not only complete this term, he will be elected for a second term, and a year or two into that second term there will be proposals to alter the constitution to allow him a third term.
The US is declining, with spiralling debt, expansion of losing wars now in their second decade (consider: if US involvement in WWII had gone as long as Afghanistan has gone so far, the war would still have been going in 1958), decline of infrastructure, lack of manufacturing of essential machinery (your transformers are all made in Europe), and so on. During such a decline, political parties have 3 options:
1. find a way to decline gracefully
2. deny there is a decline
3. offer a solution to reverse the decline
The first is not acceptable to Americans, it rarely is to declining Great Powers. The second is an obvious ignoring of reality, which is why so many politicians were knocked back (not only Clinton, but Sanders, and a stack of people in both parties). That leaves the third.
Now, there almost certainly
is no solution, or if there is it requires systemic changes which Americans would never accept, like getting rid of private automobiles, massive import tariffs (goodbye Walmart), withdrawal of US troops worldwide and turning the US military into a small force for self-defence, raising taxes
and cutting benefits like old age pensions, or else repudiating all foreign-held debt, and so on. But none of those solutions would be acceptable to most Americans.
Thus, we are left with people who merely
talk about solutions, like the Orange Buffoon. Which is why he will not only get through his whole first term, but get a second. The fact that he does not actually Make America Great Again will be irrelevant, it'll all be someone else's fault; in this he is like most political leaders, always blaming the last government for all the troubles, even if it was ten years ago.
Have fun! America. LOL.