Granted there are issues in Prime (Which software does not? Either people bitch about a software product or nobody uses it) but the context of the discussion here was comparison between the likes of Amazon and the likes of Cognizant. Tell me which Cognizant or Wipro can execute something like Prime Video in Bangalore and take it to market like Amazon has with even half as much quality?
What is the alternative you are hinting at? That someone should not work for Amazon and work on developing and improving their Prime product just because it has got issues and instead go develop a AJAX-based chat application that does not work on anything other than IE in Cognizant?
Why do you think Amazon pays 4 times the salary Cognizant pays its employees? Because developing something like Amazon Prime at the scale Amazon works at is hard. There are people who enjoy working on such hard problems even if the solution is not perfect.