Your book discovery process may be optimal for you, but I couldn't be further away from that. I don't really care to know Bob or Sally's taste at the local bookstore, don't know them, have 0 trust in them. (There's probably exceptions, insignificant ones though, in big cities like Austin with really cool book stores & a niche collector-kinda collection, but that's a different market to me)
Why would I care about human curated isles and shelves when I could go look up what Tyler Cowen's reading and recommending, or Marc Andreessen or Patrick Collison? Not to mention, Twitter's fantastic for this. There's very interesting people that post snippets as well of what they're reading, and build up a credibility that gives you insight into the book as well as knowing this person has a reading taste that aligns with your own.
And then once I evaluate the options, I can easily go on Amazon and get whatever I want to read in a timely manner (Not to mention using Amazon's reviews as an additional filter, the 2/3 star reviews for more critical analysis)
I think those can be two completely different tastes.
I agree with you that buying on Amazon is easy and frictionless but convenience comes with at a cost and sometimes price is not money. If you already know the book you want, it is dead easy to buy on Amazon. But, it is also easy to buy elsewhere online. Amazon is a bully and its business practices harm authors and publishers. It also treats their workers poorly. Is this the company you want to fund?