If they're going to comingle goods, then they need to put their own tracking onto the goods so that it is possible to know who provided the goods to which buyers. Either that or require that each item has a unique rfid or other identifier. This would allow tracing of counterfeit goods back to the supplier.
As it is, when you buy something that turns out to not be legit, you have no real recourse, and often the wrong supplier gets dinged.
1. Only stock counterfeit-prone items verifiably sourced from the real manufacturer, e.g. Apple, LV, Bose, etc.
2. Stop commingling inventory from multiple sources, which totally prevents any crowd-sourced detection of counterfeit sellers.
3. Increase manpower devoted counterfeit detection and enforcement. This could even include randomly pulling items from inventory and testing/inspecting them.
4. Detect obviously fake items, such as 1 TB microSD cards priced at $10. This can done through pre-listing manual reviews plus automation.
5. Give users obvious ways to signal the mothership about counterfeits, and take action on the signals.
6. etc.
In short there's all kinds of stuff a company with the resources of Amazon can do to solve this problem. The fact that they're doing nothing is telling.
Are you suggesting Jeff The Genius - who has aspirations to put a man on the moon - can't figure something out? Somehow?
The better question: Why are they doing nothing?
The answer is obvious.
Less than ideal example? Possibly. But still valid.
Amazon. One of the few 800 lb tech terrors. And they're doing what to solve this problem? Tolerate is being too kind. When you're making the choices they're making you're an enabler.
All the revenue. All those resources and...that gets them a free pass? That's disturbing.