Additionally, you need software to run on-prem. Rare is the application that is simply an executable running on a server and not having any dependencies on thin

Additionally, you need software to run on-prem. Rare is the application that is simply an executable running on a server and not having any dependencies on things such as databases. That software requires licensing, and there's always on ongoing annual tail that will be charged. On AWS all that licensing and support is rolled into their pricing. That turns out to be a substantial savings, along with all the other things you've mentioned.