I don’t know why I’m being downvoted - Amazon FBA does not commingle seller inventory. The products sold by a seller are only the ones they shipped to FBA. If you request your inventory back, you will only get the ones back you sell. So if a seller sends in a bunch of counterfeit items for a listing, those are physically separated and don’t get mixed with the good inventory that is there.
There are multiple sellers for the same product and they could definitely have bad/old inventory - and they will win the buy box with the lowest price - but it’s still not commingled.
I think you’re being downvoted because what you state is contrary to what most people have heard: i.e. that inventory for the same SKU from different sellers is in fact commingled. You might want to provide some citations if you want to convince people otherwise.
There are multiple sellers for the same product and they could definitely have bad/old inventory - and they will win the buy box with the lowest price - but it’s still not commingled.