That's true, although it's less unheard-of to have 24/7 public transit going ~20 miles out radially, providing about ~40 mile end-to-end coverage. Chicago runs

That's true, although it's less unheard-of to have 24/7 public transit going ~20 miles out radially, providing about ~40 mile end-to-end coverage. Chicago runs two of its lines 24/7 (Red and Blue), which provide service about 15-20 miles to the N, S, & W. The 24/7 NY Subway, PATH, and LIRR service will take you similar distances. If BART ran those kinds of distances 24/7, it would at least significantly increase the consistently-reachable zone. There's currently some all-nighter bus service, but it's not a great replacement (slow, nobody knows the routes, etc.).