The median age of Americans is 36.8 years, and from the graph at right it looks like about a third of us are over age 50. So 50 years later, the country is mostly populated by people who don't remember where they were when Kennedy was assassinated, because they weren't anywhere.
I don't really know how significantly the assassination changed history. Lyndon Johnson was probably the most significant president after FDR, with impressive achievements on civil rights, Medicare, and the War on Poverty, and a disaster in Vietnam. How do all those things go in the counterfactual scenario where Kennedy becomes president? My impression is that his approach wouldn't be too different from Johnson's, but I'm not at all confident about this. If it's true that it would've all gone more or less the same way, the assassination becomes more a moment of Baby Boomer cultural memory than a turning point in the history of anything that matters.
I don't really know how significantly the assassination changed history. Lyndon Johnson was probably the most significant president after FDR, with impressive achievements on civil rights, Medicare, and the War on Poverty, and a disaster in Vietnam. How do all those things go in the counterfactual scenario where Kennedy becomes president? My impression is that his approach wouldn't be too different from Johnson's, but I'm not at all confident about this. If it's true that it would've all gone more or less the same way, the assassination becomes more a moment of Baby Boomer cultural memory than a turning point in the history of anything that matters.