The Future of the Subway Payphone…

Do any of these subway phones actually work?  And why don't cellphones have service underground yet? 

Payphones have been a dying breed in NYC for a long time now.  But every now & then, you'll still see one somewhere.  You'll see them in the subway sometimes — the one place where you still don't have cell service & might actually need a payphone. But, of course, the payphone you find on the subway is often pretty gross & dirty, and also conveniently not working!  So what gives?  How much longer til we can get a signal underground?