That's plain naked rentseeking. I'd get them charging a nominal sum to prevent abuse (like "why I'd buy any books if I can just check out everything for free in the library" - virtually nobody ever says that but maybe they're afraid of it) but $55 is way over the cost of an average book, let alone ebook, and expiring them makes zero sense since popular book stops bringing substantial income quite soon so they literally lose nothing allowing the library to keep it.
It's surely competitive with physical books, including the cost of storing and handling them, otherwise libraries wouldn't buy them. A random on the internet says about library books: "Very popular hardcover books have a lifespan of around 20 circulations, which is around a year or less, depending on how well bound they are and how well the patrons treat them." Other books are regularly thrown away because they're not popular enough. So I presume publishers account for the short life of a library book in their pricing, and if they actually lasted forever, they'd cost more.
