Concurrency: A Primer

Perhaps that's why the next line reads:

Parallelism: Parallelism happens when at least two units of work are executing simultaneously. It’s notable that you can support concurrency on a single processor system using appropriate scheduling, while parallelism requires multiple processors or systems.

Yep: https://blog.golang.org/concurrency-is-not-parallelism

I also take issue with the idea that concurrency implies that each unit of work is continuously making progress.