I guess this goes to show how unrepresentative online commentary can be, and how easily unrepresentative info can distort our mental model of the world.

Far from "not still being a thing", Amazon is absolutely massive in the US, and usage continues to grow at a fast clip. I've never had a problem with fake goods, and I've never met anyone in person who has. Then again, I buy primarily from Amazon or the manufacturer selling on Amazon. It might be because the UI pushes third party sellers.

It is likely the same people in every thread complaining about the issues they find in some niche book market most people don't care about. They are likely telling the truth but it also probably doesn't affect that many people.

I would agree that the problem decreases with the popularity and recency of the book. If you're talking about a newly published bestseller, which is what I imagine most people buy, your chances of running across a fake are pretty small in my experience.

I would be afraid that this could change that, though - especially when e-book editions are released concurrently, it takes only a modicum of effort for a scammer to pirate the book and produce a realistic looking fake. (The advantage here, I suppose, is at least the presence of an official e-book means a professionally edited fake, rather than what you tend to see for out-of-print/old books.) Part of what makes that experience so much smoother is generally speaking, right now, if you go search for a new and/or very popular book, you'll be buying from the publisher or from Amazon.

How would you know that you didn't receive a counterfeit​?

If I can't tell the difference, does it matter to me?