Yes, there is a reason this is in GD. I don’t want an MPSIMS joke fest here.
Assuming for the moment humans still exist and are still recognizably modern humans and still have classes similar to 100-level college courses now, what would the 20th century portion of the “History of the Earth” class look like circa 3000? For example, at least a few people, myself included, think that the World Wars will be elided into a single ‘event’ much the same way the Hundred Years’ War was created out of many little conflicts. I think this will be concomitant with a general ‘evening’ of history, where Pearl Harbor and Gallipoli stand on even footing with the major events of the Chinese and Spanish and Russian Civil Wars: that is, largely forgotten except by historians and nerds.
In fact, I will go farther and say the military history of the 20th century will be largely dominated by one huge global uprising, the Hemoclysm (Greek: blood flood), that began in 1911 with the Chinese Civil War and ended and ended in the 1990s with the collapse of the majority of Soviet states and puppets, ending the largely forgotten proxy wars and the biggest single arbitrary division of humanity to that date. Most of the specific incidents within that period will be ignored by the majority of people and glossed over in any 100-level course, with only a few poking up as dramatic examples of how the Hemoclysm progressed at specific places and times.
What people will make the cut? Philo Farnsworth and Henry Ford were both more important than Hitler and Stalin, but all of them will get mentioned. In general, I think more scientists and inventors will get mentions than military/political thugs, because the technological aspects of the 20th century will have a longer reach than the political ones. People will know John Glenn and Neil Armstrong longer than they will know the people who sent them, just like the names Columbus and Drake and Cabot have outlived the names of the vast majority of the politicians from that era.