You’re ignoring general heavy workloads such as observability. How much telemetry do they gather and analyze for tracking and fraud detection. A quick google on Tesco engineering shows that they process 35k qps against couchbase, and 35 terrabytes of telemetry data per day. They track 150k devices in their ecosystem, which, reading between the lines, would produce the telemetry and require observability, state management, anomaly detection, etc. They have hundreds of thousands of employees using these devices for varying purposes. We’re talking quite a bit of compute, which also requires high availability.

I know nothing about Tesco beyond that quick google search, but I’ve been at several companies where I would read online comments claiming we could reduce our workload to a few servers, and I would think of our tens of thousands of fully loaded machines and roll my eyes.