> A hard lesson you learn building a complex system is that its reliability is the minimum of the combined reliability of its critical parts.

It's worse than that, the combined availability is the product of all components in the critical path. If your software, the authentication layer, and the cloud provider each have 99% availability, and any one of them can bring your service down, then your final availability is just 97%. With eleven components like that you have zero nines of availability.

That's why reducing components and going for reliable solutions is so important. I'm happy that the team took this path.