It actually is, most papers written today are cut and paste jobs with multiple people writing one section. The quality and focus from one paragraph to another can change. I think the lack of computers helped a bit as well for the quality of earlier papers. There used to be a lot of effort needed to publish a single paper since computers couldn't do typesetting.

Aside from that he has what comes off as a very clear mind. If you haven't I would highly recommend reading his papers. Coherent is a good adjective to describe his work.

They are easy to understand even for average people.