I'm not doubting that there are a shit ton of counterfeits on Amazon, but I am wondering how I've managed to avoid them so well. I have literally never received something from Amazon that I thought even had the possibility of being fake.

Could it have to do with the specific categories I shop in? Maybe the stuff I buy from Amazon just isn't profitable enough for the bad guys to bother counterfeiting?

Same here. I don't doubt people's experiences, but I have never received a counterfeit product while shopping relatively heavily and in various categories (electronics, baby clothing and food, books, kitchenware, stationery, etc.).

Maybe you do have one that’s counterfeit but is functionally ok? I had several items that didn’t pass (a Braun thermostat and a wheeled kitchen stool).

I suppose that's possible, but if the thing I got works just as well as the thing I ordered, what's the difference?