Personally I've switched away from amazon, after twice in a row getting a box with a switched item (HDD and SSD, respectively, both replaced with smaller and cheaper versions, and both "Sold by and shipped from Amazon"). Amazon support was good, they replaced the product, but it's a hassle to have to return-ship and wait. Now I either buy off aliexpress (if I'm okay with cheap/counterfeit, which is fine for many items) or local stores (if it's a product where I really care about quality).
That's the point. The only way to buy genuine product, not co-mingled, will be buy it Amazon labeled.
Many Chinese brands have official stores at Aliexpress by the way, so you don't need to be okay with fakes if you don't want to. Not so many as at Tmall, but still.
There may be ancillary benefits, like increased seller competition into their monopsony, but it's not a priority for them to fix, because apparently it doesn't affect their bottom line enough.
It's not like it's hard to come up with a solution to the problem - they have lots of ways of surfacing prime-eligible items, you could have a similar way of surfacing manufacturer-approved resellers for some items. And as others have mentioned, there are no counterfeit kindles on amazon.com
But really it is, because judging on comments here, people are looking at aliexpress when they don't care that they are buying a cheap chinese product.
If Amazon is known as the place where you pay for a brand and get a counterfeit, and aliexpress is where you can just pay less for the counterfeit, that seems to me like a problem Amazon would want to fix.
But honestly, we're probably just a blip.
Examples of things I would not buy knockoff/counterfeit would be power supplies, battery packs or anything dealing line voltage due to the obvious fire hazard. Examples of things I am fine with buying off aliexpress might be flash programmers, project boxes, clothes, etc.
Also, the examples I gave off amazon were not counterfeits, but rather wrong products. I bought a 12TB HDD and received a 6TB one from the same brand. Obviously I'm not okay with that, having paid full price for the 12TB one.
Seems pretty simple, right?
It is an interesting contrast, but wouldn't be surprising.
If not, let's hope that this eventually creates incentive for Amazon to handle the counterfeiting problem to protect their own brands.
If so, one would hope that Amazon is able to extend whatever tech/business practices are protecting these private label brands to other product on Amazon?