Soviet Union, Venezuela, CCP China, ...

Communism does not reward the top producers to produce.
In fact, as a political environ, it destroys people who stand out.

80% of the production is done by 20% of the people.
If you destroy the reward for these people, you only have 20% of the production left.
And so, inevitably a communist govern-cement system will starve its people.

Now, about the book. Chapter 9

You know those pictures you can see two different ways?
two people or a vase? 9 dolphins...

Well, you see it one way, and are asking me to show it the other way.
Very difficult, maybe impossible.

But some pointers.
The author/speaker does not apply the same logic to the "capitalists" and the "workers"
the capitalists do not spend all their money
the workers can't save their money.
(two very different applications of judgement. But one that is actually indicative of getting ahead in life. Delayed gratification.)

Basically it comes down to this.
The pie is getting bigger.

People on the socialist side usually try to argue about getting a bigger slice of the pie.
People on the capitalist side talk about making the pie bigger.

The thing the speaker really fails to call into account is that there are more shoes now.
And they are most likely cheaper than they were before.