Why do so many commenters on HN always sound so confident, yet none of them work in publishing? First off, if the only publisher you have a problem with is Elsevier, you have already shown your hand. A half dozen other publishers are more expensive, but you can only name Elsevier. That means you're just repeating a meme that started on forums like this one. So take a moment and ask yourself why any of these publisher…
To rephrase the question and make it less interesting: Why is it that none of the people who think that academic publishing is a scam are academic publishers?
It's like asking why abolitionists never seem to own slaves, or to show any understanding of a slaveholder's overhead.