Winning going on what, 10 15 years now? Surely at some point they must start scaling?
At this point all I can imagine is that every year they run the numbers and arrive at "yup, still makes no sense whatsoever". And so its eternally doomed to tech demo status.
They've been scaling quite rapidly lately. From the the look of it by end of next year it will be commercially available in a dozen+ major US cities.