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.
> Limits. You may borrow at any one time, 100 total items per library card, including up to 10 console games and up to 30 DVDs/Blu-rays.
Also, per-borrower limits are different from per-book limits.
A limit of 20 holds for a given e-book means that at most 20 people can wait in a queue for the opportunity to be the next borrower.
Libraries certainly do this. Might not be at (your suggested) 75/100 rates, but if a physical book is popular, library systems do purchase more copies.