The publishers are playing shit games with faculty and providing free access for them to high quality instructional materials. To the point that the faculty doesn't really have to do anything for online classes(which is a whole other ball of shit).

The secret to why they can provide this?

The content is locked behind a code the student has to buy that provides access to the book or comes with the book.

It's absolutely disgusting. For profit bullshit is fucking the youth of America. It's disgusting.

Source; the three times I've failed to push my current instruction to open access materials instead of McGraw Hill bullshit. And it failed because the lazy ass faculty can't be bothered to develop their own lessons anymore. Fuck.

You are talking about textbooks, I was talking about research publications: monographs, collections of articles, and reference books.