This feels like the tech equivalent of tax avoidance.

If too many people do this - AWS will "just close the loophole".

There's not one AWS - there are probably dozens if not hundreds of AWS - each with their own KPIs. One wants to reduce your spend - but not tell you how to really reduce your spend.

If you make something complex enough (AWS) - it will be impossible for customers to optimize in any one factor - as everything is complected together.