I saved my previous company $4000-5000/mo on AWS billing just by auditing the AWS account and turning off unused machines that that old devs has spun up and del

I saved my previous company $4000-5000/mo on AWS billing just by auditing the AWS account and turning off unused machines that that old devs has spun up and deleting hard drives after backing them up to S3, just in case. No one had really even bothered looking at it for years and I did it in my "free time" at work without being tasked with it. Ironically, I asked for a raise a year later and was denied, despite single handedly saving the company nearly $50000/yr. The raise I asked for wasn't close the cost savings I had brought. I left the company shortly after. I saw someone else have a similar experience here and a comment to it was saying rewarding this produces a bad incentive...well, honestly why would I have even bothered cutting costs if I felt I wouldn't be rewarded? Not rewarding it just makes me half regret doing it at all.