Agatha Christie won't turn to vinegar in the vault

So Sunday I watched a mystery movie that seems to be in a series called Mystery Woman - I don't remember what this entry was called. But it opened when the bookstore owner came in gloating over a first-edition Agatha Christie, for whom she had a buyer already lined up. Her ... partner? employee? token black character who (of course) had magical tech skills and also was (of course) much older than our heroine ... started bitching about people who buy first editions and wrap them in plastic and never read them. When you buy a bottle from a great vintage, he ranted, you don't let it turn to vinegar in your cellar; you drink it.

Well, yes. But two things occur to me. First, that first edition isn't going to go bad. As long as somebody's willing to pay for it, it will hold its value. Nobody's going to look at it and exclaim "Oh, you waited too long to read it! All the print has melted away!"

And second - how the hell does he know the owner of that book didn't buy a second copy to read?