I think the time estimates depend heavily on the field. A mathematician recently told him that it would take him 1-2 weeks (with nothing else to do in that time) to digest a paper outside his main area.
I'm not saying proof isn't important or to exclude it. But given that more people understand plain and intuitive explanation (at the expense of accuracy, maybe), their hard work reaches broader audience that way. Isn't that what authors want, instead of "dog whistling"? Do proofs alone carry intuition? I don't think so.
But there are natural limits. Usually, after working for years on a problem, you become so close to it that describing to a general technical audience is very difficult. Often, after you publish the work, someone else will do the difficult work of understanding your paper, and then write a more readable exposition as part of a review paper or book.