New is not always better.

For example, from about 1960-2010, anthropologists universally held a "pots, not people" view of prehistory: they asserted, with great confidence, that styles of pottery and metalworking changed over time due to voluntary exchange of ideas among peaceful, cooperating peoples. These anthropologists asserted that pre-1960 theories that pottery styles changed because population groups violently replaced each other were not only wrong, but immoral and barbaric. To them, it was modernity that made humans violent.

Now due to ancient DNA, we know that the pre-1960s anthropologists were right and the post-1960 consensus was wrong: prehistory was violent and populations violently replaced each other with regularity.

You're more informed reading, say, Gordon Child book from 1920 than a serious book on prehistoric archaeology from 2000.

So it goes in many fields. Imagine how much longer it would take for science's self correction mechanism to operate if our knowledge were encoded solely in a "living" information system aligned with only currently fashionable ideas.

But wouldn't you agree reading about this topic now, with the counter-argument of the post-1960 consensus (though I have a hard time thinking most things debatable like this are ever strictly consensus), and the follow-up DNA evidence, is far more informative and convincing than what you would read in 1920? It seems that the people guessing from 1920 might've had about as much chance of being right as the people guessing in 1960 with neither having the relevant evidence to back their claim.

Come on: if you're excavating an ancient village and find a layer of charcoal littered with arrowheads and skulls and find totally different pottery before and after the charcoal layer, then unless your brain has been codrycepted by fashionable academic nonsense, you're going to conclude that someone conquered that village and replaced its people --- not that the charcoal layer represents some kind of ceremonial swords-to-plowshares peaceful pottery replacement ceremony. For 50 years, academics insisted on the latter interpretation. If you'd read old books, you'd know the post-1960s consensus was nonsense even without ancient DNA. Ancient DNA merely created a body of evidence so totally compelling that not even diffusionists (the "pots not people" crowd) could stick to their stories and keep a straight face.