The author is confusing concurrency with parallelism. Processes on modern OSes run concurrently. They may also run in parallel -- depending on how many cores the CPU has, or even the number of CPUs in the system.
The author does indeed describe something which is concurrency (so phrased because the other direction may not be true), but it is described correctly as the "illusion of parallelism". To the user, the tasks aren't happening one at a time, but all at once.
It is cool to say illusion and magic but we do have a technical term for this: abstraction
Either you can break a problem up or you can't. It's kind of on you and the shoulders of the giants we all stand upon.