Most papers don't deserve to be in textbooks, as they are of very minor interest by themselves. Textbooks distill the fundamental bits. I agree with your other

Most papers don't deserve to be in textbooks, as they are of very minor interest by themselves. Textbooks distill the fundamental bits. I agree with your other points, and many authors do work hard to give an intuitive description. Intuitive, that is, to a reader skilled in the art. But don't think that just because you don't understand a paper that means it is overly complicated or obtuse. It might be perfectly compact and straightforward if you are familiar with the field and its conventions and notation. And this is the most efficient way to communicate. Of course, some researchers just suck at writing. A few might even be trying to sound fancy and make things sound complicated or high-falutin'. Grad students start out with this tendency, but we try to beat it out of them ASAP. Some are never redeemed. But I like to think my group produces readable papers.