I hope I don't prove to be too detrimental to your health.
"Developer time is often more expensive, but it's always a one-off cost. Machine costs are ongoing. Machines can also impose hard limits on scalability."
A one off cost? I have never seen a codebase which gained consciousness, became self operating, fixed the bugs in itself and implemented new features, I hope I will, that's gonna be a truly glorious moment for humanity.
"Ever play a computer game?"
I did, but Go is rarely used for creating games. Typical use case: backend server services.
"In the meantime if you're working on an MVP, by all means optimise for developer time. In that context it's almost always the right decision."
Yes! On this site most people are working on some startup which will fail in 2 years. Performance is barely an issue.