Even if it can't it still can be incredibly valuable in a lot of climates where it operates well most of the time(ie most of California at this point). Most people don't travel very far and where they do is probably well mapped. Google could solve a small percentage of the problem and still win.
From the source: "Data from multiple passes by a special sensor vehicle must later be pored over, meter by meter, by both computers and humans. It’s vastly more effort than what’s needed for Google Maps." In other words, the mapping required is very specific and doesn't exist. Current maps don't help.
I took a couple of other things away from that:
"We know how to make these maps, we just haven't made them yet"
"We can still see ways to improve this process"