I buy everything on Amazon, and I've never had this problem. Do you have any data to back up this claim?
From a quick search (says “Apple Computer”, but tell me if that’s really made by Apple or not): https://www.amazon.com/gp/aw/d/B0787CFNRQ/ref=mp_s_a_1_3?ie=...
Another example from another quick search: https://www.amazon.com/gp/aw/d/B075CTVSVB/ref=mp_s_a_1_12?ie...
If you buy something used, or something with a lot of knockoffs (Xiaomi) or old tech (GameCube Controllers) there is a chance you will get a counterfeit.
I switched to buying all that stuff from eBay and it's much better. Untrusted-by-default makes eBay a very healthy marketplace to buy and sell in.
Then within the last year I've started receiving probably one out of five products being very blatant fakes. I only order Prime items and only sold from the manufacturer and only brand name, but I still get counterfeit items. It's actually driven me back to retail stores for items where I 100% need to get the real thing.
Amazon is quite often not the lowest price. And, while they do still seem to be quite liberal with "send it back and we'll refund plus <mumble>", that doesn't matter if you can't get a genuine product because of all the counterfeits.