Have you ever thought about that sci-fi trope of going back in time to kill baby (fill in the blank – in most cases, Hitler)?
For the sake of argument, let's say that it's possible. You go back and successfully take Hitler out of the equation. What then? You immediately change all the future timelines of anyone and everything that Hitler touched. Yes, you saved the lives of 6 million Jews but it could then be argued that there'd be no need for the state of Israel to be formed. Einstein and German rocket scientists remain in Germany, leaving the very real possibility that the German flag would be flying on the moon, not to mention they'd most likely be the first country to possess a nuclear weapon.
No World War II, no baby boomer generation, and probably none of the myriad scientific advancements that came out of the US and its allies because of the war.
My view of this thought exercise is that someone will rise fill the void to recreate the timeline as much as possible. If there's no Hitler (or Trump), there would be someone very much like him that brings about the same general timeline that you attempted to change.
And who's to say someone from our future has not traveled back to our time to take out someone who creates a future hell?
What say you?