In Germany I've never had this problem and never heard of others having it.
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.
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.