Hard to say or tell. Candidates must decide themselves nowadays whether to run or not. Who will rise up and challenge? Who knows? It's hard to tell what type of candidate America will be ready for. Carter won because folks wanted a more honest and truthful president than Nixon. Carter, a religious man, an honest one fit the bill.
Carter proved to be inept in many areas, honest, truthful, but inept. Along came the cowboy. America was tired of being the loser, Vietnam, Iran Hostages, high oil and gas prices, they went with someone opposite of Carter. Someone who many thought was a risk taker, but one who would challenge our enemies.
W. brought moral values to the White House to replace the immoral Bill Clinton. With the economy in recession, Obama offered hope and change. People tired of Obama policies, not so much the man, they tired of business as usual in Washington, taking care of the lobbyist, the corporations, wall street firms, the mega money donors to each party, Trump appealed as an outsider. Much like Jimmy Carter was an outsider along to a certain extent, so too was Bill Clinton.
We probably go back to an insider politician. Someone who has been in politics all their lives without having a real job. An establishment candidate who doesn't make waves. One who smiles, has a persona of a used car salesman instead of an ogre. Whom that will be is any one guess.