Nowhere in that does it say “we did zero benchmarking and just went with hearsay”. Basing things on industry data is solid - looking at the steam hardware surveys if a good way to figure out the variety of hardware used without commissioning your own reports. Tech choices are no different.

Do you benchmark every single decision you make on every system on every project you work on? Do you check that redis operation is actually O(1) or do you rely on hearsay. Do you benchmark every single SQL query, every DTO, the overhead of the DI Framework, connection pooler, json serializer, log formatter? Do you ever rely on your own knowledge without verifying the assumptions? Of course you do - you’re human and we have to make some baseline assumptions, and sometimes they’re wrong.