The Constitution mentioned a "direct" taxation power of the fedgov twice. Did that mean something other than taxation of individuals? It may be that the fedgov did not avail itself of the power before 1913.
“Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.”
taxes were intended to be leveled at the state, not the individual. taxes due by the state were equal to their portion of the nations population. what tax scheme the state employed to collect the taxes was up to them.