Yes, that is basically the job description; the point of a PhD is to contribute new knowledge.

PhD's doesn't contribute new knowledge, they contribute knowledge that can't be proven to be old.

It might sound similar, but it is not. Let me explain the difference:

A person performs a study creating lots of data. If he wanted to contribute to human knowledge he would publish the data with no comments, as he is probably not the best person in the world to analyze this data. If on the other hand he was a PhD he would not publish the data, instead he would publish some pet theories related to the data so that he can build his brand, and most of all he will absolutely not publish the data since it could possibly be used to prove that his pet theories are not relevant or maybe even wrong which would be disastrous for his brand.

Now there are of course PhD's who do the right thing but it doesn't benefit their career at all.

I would argue that, while the pursuit of new knowledge is surely admirable, not all of it can be assumed to meet the high bar of being of "great value to history and humankind".

But in fact most often old topics are revisited with slightly different approaches.