All the line items are decent things, worth doing, but the claim about how much following the line items would improve reliability is super exaggerated.

> [Most production incidents] are due to the code entering a state that should never have been possible.

I have never seen evidence that this is even remotely true, and I've been looking at software reliability research in the last few months.

Instead, it is more true that most production incidents are due to the system entering into one of thousands of unsafe states which were possible and latent in production potentially for years. In a sufficiently complex system—all interesting and important software projects—functional programming is not strong enough a tool to prevent even a sliver of potential accidents.

> Arguments that these degraded conditions should have been recognized before the overt accident are usually predicated on naïve notions of system performance. System operations are dynamic, with components (organizational, human, technical) failing and being replaced continuously. — https://how.complexsystems.fail/