NYC: When Will The Next Bus Arrive?

It's about time. Now if they only would do it for subways too. And maybe people can be trained not to walk down into the subway when they see people coming up (don't they know a train has just arrived and left the station?!).

Electronic count down displays with expected arrival times will be placed along 34th street:
http://cityroom.blogs.nytimes.com/2009/08/11/miracle-on-34th-street-your-bus-arrival-time/
How come this can't exist everywhere?