In fact, most major transit agencies have route planners. I surmise they chose Portland because it is a medium-sized city with a simple public transit network. Trying to test a new system on something as large and complex as NYC wouldn't make any sense.

But it is true that I expected transit agencies would build sites like http://www.tastypopsicle.com/maps/cta.asp , not that Google would circumvent them. Besides the convenience of having this on the road, it'll be useful for building web applications as well since there is no API, XML feel, or other way to to plug into all the data on 511.org or mbta.com or stationmasters.com.