> They sold some simple product with good reviews, then swapped everything out for their new, more expensive product.
It isn't always the same "they", in fact I'd guess it isn't more often than not.
Sometimes a seller is shutting shop, and to make that last few pennies one of the assets they pass on is the account with products with good reviews. Another route to the same effect is apparently inactive accounts getting hacked. Maybe even active accounts, with the sterling reputation Amazon has for support it might be more hassle than it is worth for the hacked seller to do anything about it.
> It's ridiculous that Amazon doesn't catch this.
This comes under “sterling reputation Amazon has for support” when it comes to it being reported. And they have little incentive to deal with it if it isn't reported until there is a competitor that does it better and takes enough business for them to care – the inflated reviews improve sales of which they get a cut.
It isn't always the same "they", in fact I'd guess it isn't more often than not.
Sometimes a seller is shutting shop, and to make that last few pennies one of the assets they pass on is the account with products with good reviews. Another route to the same effect is apparently inactive accounts getting hacked. Maybe even active accounts, with the sterling reputation Amazon has for support it might be more hassle than it is worth for the hacked seller to do anything about it.
> It's ridiculous that Amazon doesn't catch this.
This comes under “sterling reputation Amazon has for support” when it comes to it being reported. And they have little incentive to deal with it if it isn't reported until there is a competitor that does it better and takes enough business for them to care – the inflated reviews improve sales of which they get a cut.