Google delivers ranking results based on relevancy above all else. The most relevant result for any search in Google will be pulled from sites that are geographically tied to the country of the search origin as a default.

This has been tested and proven by SEO professionals around the world. It can be a little more expensive but it will be difficult to rank a .com in the majority of the search results where a .co.au or .co.uk populates the results.

How many foreign websites do you see in the search results for searches done in the US? I do not see many, unless searching for foreign websites or topics.