Public libraries pay a different, greater license fee for ebooks they can lend vs physical books . The licenses also come with restrictions about number of lends, time limits, etc.
I dont think average folks care about transparency, they mostly care about the bottom line. I would bet that if you offered a black-box $50/month with no explanation and a transparent, easily understood $60/month people would choose the cheaper option 9 times out of 9.
https://www.forbes.com/sites/ellenduffer/2019/01/30/librarie...