The economics behind measuring reactive power is due to the impact it has on conductor size -- with particular emphasis upon the heavy industrial user with lots of motor loads.
Reactive power demand is met by increasing the conductor size -- not the prime mover nor the heat rate at the power plant.
Since reactive loads ( motor loads, ballasts ) are such a trivial fraction of most residential services it has never paid for the utilities to meter it. Instead, a 80% power factor, lagging, is built right into the NEC service load calculations.
So selling capacitance/reactive correction is snake-oil-in-a-can.
