Earlier quoted context omitted.
It's not third party sellers, it's comingling inventory from third party sellers. That breaks the reviews / reputation as a way to check, and it means if there's even one bad egg, even if I buy from Amazon itself, I can still get the wrong product.
It seems to me Amazon's comingling is bad for competition. Players on their platform, not between Amazon and others. Have any of the regulators taken note? I've been reading Congress' anti-trust research and reports. Haven't seen this called out yet.
Companies like Amazon are carefully engineered to avoid that type of enforcement action. Nothing will happen until you have a major political shift - I’d guess somewhere around 2035-2045 when demographics shift the political dynamic in the US.