I agree it's a nit, and your interpretation is probably on the right track, but it's an inaccurate statement by the original author as-written.

Also agree that the crux of the point is multisocket scaling. Though with enough sockets (if memory serves, in mid-2000s, the rough consensus was 4), I don't think computer architects think there is any way to scale well without a NUMA approach of some kind, so it's not just an academic point. With today's memory bandwidth and "memory transaction volume", perhaps even 2 sockets wouldn't scale well in a uniform memory access configuration.