So it sounds like the issue is that Amazon is using its weight to force suppliers into eating their platform fees rather than pass it on to the consumer.
I'm not sure of the exact numbers, but imagine Amazon takes a 10% cut of any sale on its platform. If a supplier sells a widget for $100, they'd only get $90 from an Amazon sale. Amazon is unfairly preventing them from marking up their offerings on Amazon... i.e. preventing the suppliers from selling their widgets for $100 on their direct website, and $111.1 on Amazon (so that a sale is a sale and always gets them $100 in revenue).
If a suppliers margins are razor thin this could cause them to lose money on Amazon sales... so they'd either have to mark up their product everywhere and risk losing their competitive edge, or eat the loss on Amazon... or just not "collaborate" at all with Amazon.
I'm not sure of the exact numbers, but imagine Amazon takes a 10% cut of any sale on its platform. If a supplier sells a widget for $100, they'd only get $90 from an Amazon sale. Amazon is unfairly preventing them from marking up their offerings on Amazon... i.e. preventing the suppliers from selling their widgets for $100 on their direct website, and $111.1 on Amazon (so that a sale is a sale and always gets them $100 in revenue).
If a suppliers margins are razor thin this could cause them to lose money on Amazon sales... so they'd either have to mark up their product everywhere and risk losing their competitive edge, or eat the loss on Amazon... or just not "collaborate" at all with Amazon.