The point is that the MTA is deeply in the red even though it still charges significant fares. Meanwhile, systems like the London Tube manage to recover at least their operating costs without charging fares that are much if at all higher.
According to a quick search the nyc subway is $2.90 rising to $3 next year. This is comparable to, but slightly less than a zone 1 off peak ticket in London at £2.70. Most journeys are more expensive (on the train, busses are pretty cheap here)