just because the job title is different, doesn't necessarily mean aspects of the jobs are any different.
Actually, I think you missed an essential point. In academia, publishing is usually a job requirement and key part of career advancement. This is what Seth means when he says it's part of their jobs. He is not saying it's part of their job just because they teach, there are plenty of people who teach things but are not required to publish.
distribute the same materials for free
Seth is not saying this. He is emphatically not suggesting that texbooks should be distributed for free. There is no "same materials" stated or implied.
Actually, I think you missed an essential point. In academia, publishing is usually a job requirement and key part of career advancement. This is what Seth means when he says it's part of their jobs. He is not saying it's part of their job just because they teach, there are plenty of people who teach things but are not required to publish.
distribute the same materials for free
Seth is not saying this. He is emphatically not suggesting that texbooks should be distributed for free. There is no "same materials" stated or implied.