Earlier quoted context omitted.
Those hundreds of fake reviews are a feature, not a bug for Amazon. They drive sales. And when the chickens come home to roost, as you say, Amazon will probably figure out a completely different trick to juice sales.
In the short term Amazon may benefit from this. But the fake reviews, throw-away brands, and counterfeit items are gradually corroding Amazon's credibility and brand identity among customers. This is the first year I've heard family members (who are frequent Amazon customers) complaining about these kinds of issues.
Amazon are very good at making money. This is not a problem for them; it's an opportunity.
Before Amazon lose all their credibility they'll introduce something like "Amazon Assured" that sells customers a guaranteed real item. They'll charge sellers for the privilege of having the "assured" status on the product page, and make filtering by assured status something that's only accessible to Amazon Prime users.
Users will believe Amazon are doing this to protect them.