Alright, so you actually can be a manufacturer and a retailer at the same time, just with your own products on a separate website.
Are manufacturers legally barred from linking to the marketplaces of its peers?
Could Amazon not just maintain two websites, and shut down the marketplace for certain goods when it feels it has enough information to sell its own versions on the other site?
If not, could Amazon not just sell the information it would have used to develop its own products to another company (which we'll assume is totally unrelated) to develop its own off-brand products, and then treat those products preferentially?
I think those are good implementation concerns. Maintaining two separate websites isn't really an option under the supposed regulation, that's still one company being a platform and a manufacturer. The second option seems alot more likely to be allowed -- but now, at least you've created a market for that information and it's not just Amazon that has access to the data. Not sure I understand why it would treat the those products preferentially though -- unless you're bundling selling that information with product placement fees, which doesn't seem to be related (or necessary). I would assume product placement would be another revenue stream for the platform, like it is now for brick and mortar retailers like walmart
Are manufacturers legally barred from linking to the marketplaces of its peers?
Could Amazon not just maintain two websites, and shut down the marketplace for certain goods when it feels it has enough information to sell its own versions on the other site?
If not, could Amazon not just sell the information it would have used to develop its own products to another company (which we'll assume is totally unrelated) to develop its own off-brand products, and then treat those products preferentially?