Those same libraries can then resell their excess copies a few years later at a Friends of the Library sale and recoup a few dollars. This isn’t possible with e-books currently.
Obviously, since patrons check it out, there is demand for it. Well, so what? There is demand for cocaine and porn; should public libraries offer that?
Demand for something doesn't ipso facto oblige a library to provide it.
Of course demand for something doesn't make it something that should be free.
On the other hand, your arguments against e-libraries are just as vague and lacking in implication.
Libraries promote literacy and/or learning with every book read. Even as a source of entertainment, it promotes a richer culture. All of which does have a total health of society benefit.
Why not? What are your goals of a public library?
Nothing with an expiring license or ongoing fees.