Throughput is different from availability, and I'm not conflating them. But they are not completely unrelated, either. All I'm saying is that it might turn out

Throughput is different from availability, and I'm not conflating them. But they are not completely unrelated, either. All I'm saying is that it might turn out to be more expensive to design high-availability architectures using a small number of high-throughput servers than it is to design one using a large number of low-throughput servers. Sometimes this doesn't matter because you only need to crunch data a few times a week. Other times, you need 99.99% uptime.