There's also less people that have to own cars. If NYC didn't have subways it would be unlivable given the density.
Also for what you've described to be true, you likely lived in a high income area since they provide easier access to where most offices are situated. If you're commuting in from the outer boroughs into Manhattan, driving is way slower given the traffic (and way more stressful, and then there's the parking situation).
If NYC did not have subways, it wouldn’t be as dense. It would be a totally different city with respect to culture and who lives there.
Something that is often overlooked in the transit vs private car debate is that modes of transportation affect urban design and ultimately different ways of living.
Driving in a transit oriented city is totally different than riding transit in an auto oriented city.
Also for what you've described to be true, you likely lived in a high income area since they provide easier access to where most offices are situated. If you're commuting in from the outer boroughs into Manhattan, driving is way slower given the traffic (and way more stressful, and then there's the parking situation).