Even that is minimally helpful. You can't exclude non-verified reviews in search or overall rating. You can't believe that they're in any way helpfully independent - it would be the easiest thing in the world to seed your shoddy product's life on Amazon with verified reviews from employees and friends. I've seen reviews on some products that seems to indicate this is happening at least sometimes.

Having lost trust it is going to be near impossible to regain it. You mention the Amazon/Kindle brand - they don;t, from the way they are managing it, appear to care very much about it. I used to believe the bad ebook formatting was an early days teething issue, but years later it is still relatively common.