Our understanding of the past has changed out of all recognition since I was a young man -- by which I mean that the BIG picture has changed.
The LITTLE pictures of history, like the Civil War or the French Revolution or World War II have changed to a degree as more research has been carried out -- and a lot of that has come from the availability of new records (written material) either through discovery (e.g. the Dead Sea Scrolls) or release from archives, rather than through technological progress. When I was a young man I was unaware of the code-breaking at Bletchley Park. Even now Britons are not permitted to know the truth about WWII; a visitor to the National Archives at Kew finds that many files are marked "sealed until 2045". Fifty years ago I smelled a rat over the official account of the JFK assassination, but the Zapruder film had not yet been shown to the public. Even now some documents relating to the assassination are still sealed, but in fifty years time people will know a lot more about things they will probably have ceased to care about.
The BIG picture is that we have discovered much more about human origins, although we may still only be scratching the surface. Here, technological advance, particularly in the realm of DNA, has been of transformative importance. We did not know of the Denisovans fifty years ago. I have always been interested in human origins above all other aspects of history and this is reflected in my name of River Ape -- for we are among the great apes most distinctly creatures that evolved at the riverside. (BTW I have heard that there are more places called Riverside than anything else, including Springfield, in the US.) For others for whom this topic is of interest I recommend the most important book I have read in the last fifty years: Catching Fire, How Cooking Made Us Human, by Richard Wrangham. (I won't say more; you can Google it.)
In the post Ice Age era, we have discovered that civilisation stretches back further than we supposed fifty years ago, with Gobekli Tepe causing a major rethink of time frames. Early civilisation elsewhere (e.g. at Mohenjo-Daro) has been explored far more deeply. We have learned far more about pre-Columbian Mesoamerica and Peru. Next to DNA, carbon dating has been the technological factor making the greatest impact.
More generally, we have discovered simply more and more of what was going on in ancient times -- and with that has come the realisation that populations were greater than we used to suppose. Every time we have a drought in England (and this year has been a better year for archaeologists than for farmers) aerial surveys discover the traces of more ancient sites.
Well, that will do as a start from me . . .
except to say that if you have never searched "megaliths" on YouTube, you have much to learn -- but keep an open mind!