I've made purchases from Amazon 1-2 times per week for the last few years, and have never once received an item that I suspected as counterfeit. I've ordered everything from food to everyday sundries to pretty esoteric lab equipment. I'm always very surprised by these threads on HN where people say that everything is counterfeit.
Cheap, no-name electronics are plentiful, of course. Not everyone can afford to shop at high-end electronics stores that stock only name brands. Sometimes the knockoffs work better than the original. Often times not. Why do people think the sky is falling?