> Either play it by ear, or literally double your cloud costs for a true, real prod-parallel to mitigate that risk.

There's also the problem that doubling your cloud footprint to reduce the risk of a single point of failure introduces new risks: more configuration to break, new modes of failure when both infrastructures are accidentally live and processing traffic, etc.

Back when companies typically ran their own datacenters (or otherwise heavily relied on physical devices), I was very skeptical about redundant switches, fearing the redundant hardware would cause more problems than it solved.