I'm not blind, but my father had low vision and so I know a little about the experience. It infuriates me that authors have pressured Amazon into removing the audio text reading ability of the Kindle. Such small-minded greed is indefensible.
You mean "a very small subset of all books exist in the more expensive form of an audio book". Just check the library closest to you: 10000s of books, 100s of audio books.