This glosses over availability a bit too quickly. You can't have high availability without at least dipping your toe into distributed systems. (BTW don't tell me about "single box" high availability or fault tolerant systems. I was there when they were created. They're distributed systems wrapped in tin, one with and one without extra circuitry to add complexity and cost.) A lot of people need high availability, including data availability, even if they don't need high scale.

There's a lot of jumping toward higher-than-necessary degrees of scalability, and lots of gatekeeping, but it's still true that for a lot of jobs "one beefy bare metal machine" thinking just won't allow you to meet requirements - with or without a backup that has to be promoted manually.