That doesn’t help much because 3rd parties use Amazon FBA all the time. It’s an even worse problem due to inventory commingling ie even if you buy from Amazon as a seller, there’s no guarantee that the item shipped to you is actually Amazon’s inventory unless you look at all the sellers for the item and verify that there are no other 3rd party sellers using FBA aka Prime
I have noticed certain electronics are much cheaper on AliExpress, but you do have explicit shipping costs vs that being rolled up in prime membership costs.