No, profs don't get paid for it. For the most part, it's simply the traditional, accepted way. In short, profs are persuaded to use the new edition because (a) they typically do update the content--at least some--to be in line with more-current findings on that content (b) they get new test banks, and (c) they get new powerpoints. In 2011, my pedagogy was based on (a) all online, open-access learning materials, (b) creation of novel test questions every semester--for lots of reasons, and (c) no powerpoints. Although university administrators, fellow profs, and many involved parties told me it would fail and be unsustainable, it's actually been a huge success (at all levels). There is still a lot of push back against this approach, but to date not one person has been able to argue against the data I have that evidences the overwhelming success of the approach.I wanted to hug my professors that did that. I almost wonder if they pay profs who use the current edition textbook. It's ridiculous. I bought a 9th (or whatever it was) edition textbook for calc, only to find out they were going to use the "enhanced" 9th edition - the difference was about 10-15 extra homework problems at each section, and full color vs 2-color. The extra problems I think were thrown in by the publisher to change page numbers, which made it near impossible to use the older (much cheaper) book. I was not thrilled. Another time I bought a current edition physics book ($300), dropped the class and re-enrolled the next semester to find there was a new edition. Another $300. For one class! Screw that!