You don't need thousands of servers to make it worthwhile. If you have code that runs constantly on 11 servers (possibly in k8s) that each cost $1k/month in AWS

You don't need thousands of servers to make it worthwhile. If you have code that runs constantly on 11 servers (possibly in k8s) that each cost $1k/month in AWS, and you spend a few weaks optimizing it down to needing 1 server, those weeks just generated the equivalent of a YEARLY $120k revenue stream. If you require an ROI of 5 years, no interest included, you just created $600k in value over a few weeks.