The US government encourages US companies to sell their products in other countries because as the US products get into other continents and spread into other countries, the amount of tax money coming into the US would increase dramatically.
There is a direct relation between the amount of taxes and the economy. This means that as the amount of taxes getting into the US increases, the economy of the country also increases.
Based on the above, selling US products in other countries would help improve the US economy
Hope this helps :)
