Jarrett Walker, the writer of that blog post, makes actually the same point in another post. In public transit there is a trade-off between maximizing ridership by focusing on great service on a limited number of lines, or maximizing social service by multiplying lines that go everywhere but do not offer convenient service for commuters.

Walker has long been an advocate of making that trade-off apparent so taxpayers know what they're getting, and of re-balancing networks in favor of maximizing ridership. It means fewer lines, serving dense parts of cities, and running frequently.

Edit: the ridership/coverage tradeoff http://humantransit.org/basics/the-transit-ridership-recipe#...