i suspect a good number of publishers(not authors) don't really CARE if people READ the books, only if they BUY them. if they buy them for wallpaper, or to make a dress, or to burn for heat or a political message they don't care, they get payed. to such a person a library is pointless at best, dangerous at worst (after all anyone reading a book in a library isn't PAYING for it, it may as well be theft...if libraries were new tell me you couldn't see that claim levied.)
as for ebooks in a library...it's tricky. yes, it would be rather useless, a digital file in a brick and mortar building and why? to be in some way compatible with the existing infrastructure mostly.
i'd like to see the internet ITSELF deemed a library, though even that is not quite accurate. the internet is something unique altogether. a store, a library, a bank, a phone, the list goes on. and there is no nice distinctions between them, they all blend together. you can't, for instance, say you can only read this on this site. attempts to shove these shades of grey into black and white boxes just causes problems for everyone.