I have heard non-fiction authors comment on this. It is because there is no market for a pamphlet or novella length work. In science, self help and business p

I have heard non-fiction authors comment on this. It is because there is no market for a pamphlet or novella length work. In science, self help and business people often write influential essays or academic papers. It may make sense to print them because want them as a reference, and the author can expand their ideas. But the problem is that in general they don't need to be ~250 pages.