It's really hard to build a system for the cloud that can run on bare metal unless you make that a goal of the project.
That can be a hard goal to sell to business. Especially when it requires more head count.
mensetmanusman
How do you factor in two 9s versus seven 9s of uptime?
josh_fyi
As DHH himself says here: The cloud allows flexibility, which is essential when you are figuring out what you are doing, as in a startup. If you are large and stable and know what you want, then yes, you can go on-prem. But note that the cloud providers will negotiate significant discounts for large customers.
Better to run your own machines.