I understand your metaphor in the sense that The Matrix is a scifi adaptation of the allegory of the cave. The concept that commercial/online bookstores are where items worth finding will be found is like thinking the shadows of the cave are the only thing worth seeing. You are correct, there is so much content there be found, which isn't limited/controlled by what the big market values.

Additionally those are very good points about English and streaming. There are books out there which are not translated and not digitized, which are absolutely worth reading, and will not be found anywhere besides private collections, used bookstores, flea markets, estate sales. Some of these books were originally purchased long ago and/or far away, just because they are not popular enough to be easily found does not mean they are not worh finding.