I can see where you are going with this. But there is NOT a copy in my browser. Only a representation of a fraction of the whole book at any given time. I cannot make a copy.
When I am viewing the section of the book, the rest of the book is “checked out”. No one else can look at it. Is this not how a library works? I check out an item, then I take it back? Are they not making the steps to make sure I can check it out, read it, and then I have to give it back?
Since libraries are allowed to loan from their collection, what makes digital any different? In the case of video, if the library wanted to check out a video and stream it to me, I see no difference than me checking it out myself. In fact libraries are granted the right to show videos to me and small groups, so why can’t I be farther away than in their building?
The current move of libraries to streaming services is exactly because of this. Now the library has a license, and cannot share the stream without the license. This is a move to remove physical items so that the possibility of streaming from a physical item is moot.