You are just wrong. There is a lot more that goes into teaching a subject better than 'generating a better textbook'. There are thousands of hours of work that need to happen to figure out how to make the subject make more sense. It is not a question of 'writing down known result sin a different order'. The subject needs to be reworked in its entirely. Advanced results need to be made elementary. Simple formulations of complex ideas need to be discovered, articulated, and developed into exercises. Out of every available model the best models need to be picked and refined and tested. Etc. And then you have to get everyone on board with the project!

Almost none of the work is 'rewriting the book.'