> One interesting factoid I know is that 50% of Americans represent 2% of the income in America.

Reference?

This recent study[1] suggests the bottom 50% income represents 12.5% pre-tax, 19.3% post-tax based on 2014 data.

[1] http://gabriel-zucman.eu/files/PSZ2018QJE.pdf see p. 39, Table I