This may be valid, but even if it is someone (or a group of people) at Amazon are violating one of their core leadership principles - Customer Obsession
https://www.amazon.jobs/content/en/our-workplace/leadership-...
A useful (and hopefully delightful) UX is key to showing customer obsession.
That being said, I personally feel the UX at Amazon sucks overall, not just for pricing/packaging but even getting basic shit done. So perhaps Amazon (or at least AWS) doesn't think a good UX is a key ingredient to demonstrating Customer Obsession.