If you're referring to the number of folks who work in the central business district of Manhattan but have no choice but to drive (given the enormous catchment area of MTA services), that number is vanishingly small, and congestion pricing does have low income discounts.
If you're referring to those who drive taxis or cars-for-hire in Manhattan, yes, the idea is the cost should be borne by riders who choose those services instead of transit.
If you're referring to those who drive taxis or cars-for-hire in Manhattan, yes, the idea is the cost should be borne by riders who choose those services instead of transit.