Prior to the digital age where it's possible for the author to self-publish the publisher was handling 99% of the actual business of selling books and giving authors 15%.
So while I think it's been hard to make a living as an author I don't think it's necessarily the publisher's fault. Better to be the one's selling shovels than the ones mining for gold.
Having written two novels, I will tell you it's far less work for a lot of writers to write the thing than getting decent sales. It varies - some do slave over their manuscripts for years, while others churn them out in a week, but selling books is hard work.
So while I think it's been hard to make a living as an author I don't think it's necessarily the publisher's fault. Better to be the one's selling shovels than the ones mining for gold.