I would also hesitate to label whites as the "dominant culture group", not only due to the geographically distinct cultures within the United States but the fact that ultimately, class is a far more reliable indicator of power than race (though the latter certainly has some say--see black incarceration rates for drug offenses despite using drugs at a lower rate than whites).
There's a difference between saying "whites are the dominant culture group" and "
all whites are in positions of power." And in the US at least, race and class are very interrelated:
Those are median numbers for household net worth among different racial groups in America (as of 2010).
