Just to refute the title: I've sold a dozen of my textbooks in the last two weeks. I bought them almost fifty years ago for my applied physics degree. So some people are buying some books.
But yes of course no one buys most of the books that are published, I don't suppose that Lorrain and Corson sold more than a few thousand copies of Electromagnetic fields and waves (one of the books I sold) and I doubt that they made enough money to pay for the work it must have cost them.
It must be even worse for academic textbook authors nor that many university courses don't even use textbooks any more because they have switched to modular online instruction.
But yes of course no one buys most of the books that are published, I don't suppose that Lorrain and Corson sold more than a few thousand copies of Electromagnetic fields and waves (one of the books I sold) and I doubt that they made enough money to pay for the work it must have cost them.
It must be even worse for academic textbook authors nor that many university courses don't even use textbooks any more because they have switched to modular online instruction.