It's if course never gonna happen. It's too convenient for Amazon and most users probably don't even understand that they aren't buying from Amazon.
Recently Amazon made it much harder to select sellers.
Now on some products, the page is so confusing that you don't know is it "Fullfilled by Amazon" or you are buying from someone in China.
Race to the bottom and all...
Recently I got them to refund me after showing I returned the defective item (tracking number + signed by an employee) the SAME day it was returned to the seller's location. Granted, the seller and I had a dispute (which was that the seller refused to acknowledge the device spit out a fair amount of magic smoke when powering a small charger).
Again, it's effort in and effort out. If you buy something off Amazon, make sure it's being shipped to you by Amazon!
- Search - Pick a category - Select "Amazon.com" as the seller
edit: That wasn't clear. Try two: Inventory submitted by FBA vendors is commingled with Amazon inventory in Amazon's warehouses. When you, a sucker, buys it, you have zero control over whether the widget you get was purchased by Amazon from the manufacturer or sent to Amazon by Billy Bob's Sellin' Totally Not Fake Shit Shack, which definitely got it from the manufacturer, not the bottom price on Alibaba. This is true even if you buy from Amazon and not an FBA vendor.
You can fairly consistently filter by Prime/non-Prime, but that's not the same (that filters down to things fulfilled by Amazon, but not just sold by Amazon).
Out of curiosity, why do you assume people don't realize they aren't buying from Amazon?
(Can't remember, but do the parcels come in Amazon packaging too?)
Because Amazon tells them when they're looking at the item that it's sold by a third party? And then again when they're checking out. And the items sold by third parties include an invoice and receipt from the third party? It's not a difficult technical issue - it only requires basic reading comprehension, which I'd expect most people using Amazon to posses.
Obviously everybody commenting here has figured out what's going on, and most people I've talked to about it (technical and non-technical) have also figured it out, so I just can't see it as Amazon tricking everybody.
My assumption is that most people buying from Amazon do know about and understand third party sellers, but aren't bothered by them enough to do anything.
This is your problem. Most people don't have basic reading comprehension when they're using computers, even less so when they're not expecting to be scammed. This is well known in UI and IT support circles. They don't notice details, they don't read the error messages, they don't read the fine print. On Amazon, they just want to get their thing and move on.
Even if some people understood "some inventory comes from different places," the vast majority of retail operations vet their sources and have quality control. So it's easy to understand why people would assume it's not different from Target selling inventory provided by multiple distributors.