He clearly understands the concept. What isn't understandable is why it's here at HN, why it's within the top 10 front page submissions, and why some people claim to think this idea is innovative or special. It's really nothing more than pizza delivery.
I don't think he thinks it's a "dumb" idea, either. Clearly it's at least somewhat viable, given that pizza delivery is well and alive, with many establishments being around for many years, if not decades.
But that's really what it boils down to: this is just a very limited form of the well-established, long-running practice of pizza delivery. Pizza is, after all, just freshly-baked bread delivered to one's door, but with the benefit of various toppings.
It's really absurd to see you talking about "why it's only happening now" or that "nobody ever thought of it", especially when we've been ordering pizza and having it delivered to our door in well under an hour for many, many, many years now. This is an old idea, plain and simple.