Yeah, I agree. I think it can be a case-by-case situation depending on both the reader and the publishere/author. An undergrad needing a course textbook that's published by a monopolistic cartel with a 300% markup? Absolutely. For well-paid worker in a developed country buying a novel written by a niche author? probably not the right thing to do.

It's very unclear how book sales translate into income for authors. You are rewarding middlemen; these middlemen have a role that may or may not be important these days.