The libraries lent physical books without any contracts. What publishers want is to make so that the rules and rights regrading physical books do not apply to digital books; what IA wants is to allow libraries treat and lend digital books the same way as physical, without permission from the publisher.

The contracts with libraries you mention require a library to buy a license for every ebook, and renew the license periodically; the publisher may set arbitrary price and terms.

So what the publisher wants is to strip users of digital books part of their rights.