Incorrect. New York has lots of people trying to get from point A to point B pretty much all the time, and other American systems with half-decent mass transit

Incorrect. New York has lots of people trying to get from point A to point B pretty much all the time, and other American systems with half-decent mass transit (Boston, DC) also see those systems get heavy use, to the point that shutdown of a line is a major disruption. Which is also the universal experience in Europe; Paris has added several mass transit lines in recent years, and has had no problems keeping them full.