I thought the standard argument was that online courseware doesn't reduce class enrollment, but attendance. Not that either is a good reason to stop putting course materials and lectures online.
Is reducing attendance really a problem for Universities though? Universities get paid by enrolment, not attendance. I don't know if there is any drawback for individual lecturers if attendance to their lectures drop, but if there is then online material is the perfect incentive they need to up their game.
I'd say it would be a problem if half the class just doesn't show up, figuring they can just watch the lecture online later. Some professors think this will make undergrads lazy about showing up to class, and more likely to fall behind.
How is that really different from half the class not showing up, figuring they can just read the lecture notes and text book later? If it makes the students lazy and they fall behind and fail, then those students have learned a valuable lesson for next time they take that class.
