To be "fair-ish" (since I'm a biotech patent attorney) - Humalog is not a 100 year old drug. It is recombinant human insulin, which is different from insulin isolated from pigs. And as the article notes:
The most prescribed types of insulin are called analogues, which are slight variations of human insulin that aim to help diabetics' bodies function more closely to how they would if they were able to produce the insulin themselves.
Obviously, those are new drugs as well, which had to go through the entire development and clinical trials process (and costs - which are even higher for biologics). If they were not better drugs, they would probably not be the most prescribed.
This does not mean that I don't believe that the price increases haven't been exploitive, nor that the insurance companies' high deductible plans aren't nearly useless to the average person. Which is why we need universal health care, Medicare-style.
But that's a different political argument.