Having previously performed an extensive TCO calculation (2010) it was substantially cheaper for on-prem vs AWS. We had <10000 machines, mostly cheap/supermicro

Having previously performed an extensive TCO calculation (2010) it was substantially cheaper for on-prem vs AWS. We had <10000 machines, mostly cheap/supermicro. We had our own parts inventory and staff dedicated to maintaining equipment. I also ran facility operations for things like the generator, fuel testing, UPS PMs, air filters, professional cleaning, etc. You have to know your business and you need people with facilities skills. Investing in cold aisle containment reduced our PUE quite a bit. You also have to become an expert in logistics to run your own facility, where just almost anyone can click away in AWS and spend money.