Managing and occasionally slashing costs is why AWS consultants can make really good money - if you're into this kinda thing, it's worthwhile learning how to analyze and optimize AWS bills.
Well, before AWS big companies tended to have the same problem, but instead of paying for many AWS features they paid for a thousand different products and trying to make sense of all those bills for each product was hard. I know some people who worked as consultants to clean up all the services the company was paying for but didn't really need any longer, paying for around thousand different software products was the norm and not some unrealistically large number.