the one-star reviews span more like the last year or two. Bad reviews showing the products have failed badly.
You should always sort reviews by "Most recent". "Top reviews" are selected by an algorithm that pushes "helpful votes" that can be easily manipulated, among other things. It's also not uncommon for quality to dive once an item starts selling.
Seeming to be an attempt to desensitize folks to even looking at reviews anymore. I can never get to the end of the one-star without walking away from a possible purchase.