Probably this isn’t quite what the OP is looking for, but it’s almost impossible to become a memorable President. There’s George Washington, Thomas Jefferson, Abraham Lincoln, and “those guys in living memory”.
If you read 19th century literature, it’s sort of impressive how often Napoleon is mentioned, even towards the end of the century. It quickly becomes apparent that he was their Hitler. Not in the “embodiment of evil” sense, but in the “if you keep talking, eventually someone will raise the subject of Hitler” sense. Nowadays, how often do you see Napoleon being mentioned? If Trump is forced to resign or is impeached, he’ll boot Nixon from the “Worst ever President” seat. If another President is assassinated, he’ll boot JFK from the “President most taken before his time” position. We tend to have some general narrative stock characters that, once we find a more recent, relevant example, we swap out the old one for the new one and largely forget the predecessor. JFK is memorable for being youngish and being killed before being able to complete his job.
As a slightly more knowledgeable person than the average and regular poster on the SDMB I am more aware of Madison, Jackson, and the two Roosevelts and might add them to a pool of “commonly known Presidents”, but I suspect that if I went out and interviewed your average person on the street, I wouldn’t be surprised if most of them couldn’t tell you a thing about them except by guessing that if they’re old, dead, and famous then maybe they were the President?
Franklin Pierce was a youngish, good looking President whose 11 year old boy was gruesomely killed just days before he took office. That seems like a pretty good comparison to JFK. Granted, JFKs legacy is better than Pierce’s, but if you asked me if there was ever a famous person named “Franklin Pierce” is history, I’d have to honestly answer “Minus Wikipedia, not that I’m aware of.”
By 2117, with no one around that was alive at the same time as it, I don’t know that even the Cold War will still be remembered. JFK certainly will not. Maybe there will be someone that fills a similar niche in the minds of those future Americans, but it won’t be JFK.