Well, I'm practically some flavor of communist and would like to see all of society organized in a fundamentally different way :)
But that's not helpful, and I think it's not what you're asking. To answer your question pragmatically, no, of course I do not "expect authors or publishers to operate without a profit motive." I think art is very important, and under a capitalist society, I want artists and (to a lesser extent) publishers to get paid to they can buy food and have a nice place to live.
Public libraries themselves do not work on a profit model, though. Libraries buy books, but libraries themselves are not profit-driven. They do not sell a service, and instead receive money through other ways. Rather than understanding Overdrive/Libby as a product to be bought by libraries (analogous to physical books), I would rather see Overdrive/Libby/something-else to be understood as a service that is offered by the library (analagous to the librarian checking out books). The service would have to be owned by a different kind of entity, maybe some kind of non-profit that is beholden to libraries, or some kind of federal government entity. And the service would need a different funding model (one more similar to how libraries are funded, or one more similar to how inter-state or federal projects are funded).
Perhaps you disagree, that's fine, but I hope I've articulated my position reasonably well.