I don't know. By asking Australians to make up their own mind about what they purchase over trying to bring tariffs in retaliation hopefully it will draw less ire from the the US.
Plus most staple goods are primarily Aussie made and manufactured (bread, milk etc.). So asking to think about Aussie produced products it won't massively increase the cost of living (hopefully).
Other than GOG is there even any other storefronts that don't give you a steam key that aren't American?