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.