I am not sure I understand. Aren't books "worthless" because they are readily available? Books are only expensive if they are rare (out of print, special limited edition, hand made or labor intensive, author signed, etc.). I don't think I would want "most" books to be rare and difficult to obtain.
Of course, there are rare antiquarian books that always find a buyer, but they are quite few. And perhaps nobody will mourn the vast number of cheap crime novels thrown away every day, but there is so much more: good, beautiful, high-quality books that happen to be out of fashion for the moment. These, too, are being thrown away.
It was a long time since public libraries aimed to maintain a somewhat curated (or complete-ish) collection. Nowadays it is all about statistics. If books are not borrowed often enough, they are removed from the shelves and disappear.
Perhaps I am overly pessimistic, but I fear that many, many books will, for all intents and purposes, be lost. There are so many books that aren't scanned/digitized.
But you also can find them and garage and thrift stores, languishing unsold.
Wonder Books has a concept of how to save them: https://booksbythefoot.com/about/
Which perhaps people buying books because how they look on the shelf is bad, but is it worse than the giant recycling grinder machine turning them into pulp to fuel Amazon’s Mordor-esque delivery furnaces?