The slices of the "money pie"

In one episode of the podcast Brooke says that money-wise it’s not like we share the slices of a pie, so that if one gets a bigger slice, others get smaller ones.
I agree that value-wise we don’t share the slices of a pie because we can simply bake another pie. But I don’t understand how that can be applied to money.
Money is literally printed only by the specific authority. And there is only a certain amount of money in a country at a given time, right?
And I also think that the expression “making money” is not very precise, because I would rather say that what really happens is “collecting” money from people who need and approve and value what one offers.
In Italy we use the expression “earning money” not “making“.
Recently I have also seen a video of Jeffrey Allen talking about how the material world is scarcity based (for example if you buy one copy of a CD, there is one less left for sale) and energy world is abundance-based (if you download a copy of an album there is actually one more copy in the world) – and I would say money belongs to the material world. Do you have a different evidence?
Could you also suggest a source where to read about this topic?
I am looking forward to hearing from you.