I'm sympathetic to the motivation, but the author is a bit naive in some of the specific requirements --- we absolutely must spin things up locally to retain our autonomy. Sure, allow testing in the cloud too, but don't make that the only option.

The cloud should be a tiny margin business, that it isn't shows just how untrustworthy it is. The win-win efficiency isn't there because there's so much rentier overhead.

Oh, and use Nix :).