Basically, the publishers have figured out a way to insert themselves as parasites into the system, based on the fact that many academics must publish or perish. They charge substantial rents and contribute little if any value. Mostly, they coordinate the peer reviews (for which they don't pay a dime) and handle the actual printing (of little value anymore).
It's very difficult for any individual actor in the system to opt out of using them. Untenured professors need to publish ("or perish", as they say); they are not in a position to take a stand on this issue. Libraries are disincented from cancelling individual journal subscriptions by clever bundling by the publishers.
I can understand why people wouldn't want to continue to be taken advantage of in this manner. I wouldn't either.