One thing I'll never understand about the publishing industry is how a print book can be $110 and the audiobook is $12, as it is for this title

Physical media have printing and warehousing costs, have natural scarcities like a print run, and people like them more. Audiobook has a marginal cost of production around $0.02, most of that data egress costs.

This is the standard pricing for most academic books. Main buyers are libraries which are totally not going extinct. You are lucky as an author if your book is priced under $35.