As a faculty member at a university allow me to present a different point of view. My institute dropped membership in  Access Copyright after they tried to hugely increase the fees while also adding extremely onerous new terms and restrictions. Instead they directed the funds saved towards a copyright office which vets course material to ensure compliance with the law.

In addition, some of us faculty have got so fed up with dealing with overpriced academic publishers and increasingly onerous copyright laws that we have published our own course notes using the incredibly cheap online publishers available. This has reduced the cost of textbooks for students in my courses from ~$200 to zero if they can live with a PDF (as ~90% do) or US$5+postage if they want a printed book from Amazon's CreateSpace. That's where your royalty payments have gone: measures to completely avoid or ensure compliance with increasingly complex and onerous copyright laws.