You are mistaken.
The Median Household income is 60,000 thus half have incomes MORE that the median, half are less than 60gs. No ways statistically that that half has only 30g in income.
1 In 2 Working Americans Make Less Than $30,000 A Year
https://dailycaller.com/2015/10/25/1-in-2-working-americans-make-less-than-30000-a-year/
More Than Half of U.S. Wage Earners Make Under $30,000 a Year, According to a Shocking New Report
https://www.truthdig.com/articles/more-than-half-of-u-s-wage-earners-make-under-30000-a-year-according-to-a-shocking-new-report/