Yes, you're right. It's almost impossible to purchase from a physical store or from competitors to Amazon (who many times are much bigger than Amazon in their country).
On the next episode of Oppressed Hackers: We get a load of a guy who had the nerve to say that it was possible to drink a glass of water.
The point wasn't that there are no alternatives, but that calling Amazon "only an interface to purchase products made by other companies" is reductive to the point of being completely wrong.