Note that there are "only" 209m Americans over the age of 18 [1]. Not that it makes it much more affordable. Without including medical, it looks the government spends about 1.5T already (including SS) [2]

1 http://www.infoplease.com/us/census/data/demographic.html 2 http://www.usgovernmentspending.com/year_spending_2016USbn_1...