Americans; the Hard Working
"...the somber, the honest, and the industrious...
Brooks and Dunn's "I'm proud of the house we built" represents the new Americans setting a foundation for the new country. They work hard and in the end they are proud of what is happening. In the song the "house" is referring to his family and life, but it can also represent the new world. In this case the "house" is north America.
Sum it up
The article basically say that the american people are made up of hard working ambisious people that are trying to reach their dreams, and for the most part, are succeding.