I'm not sure I totally understand your point but a) a robot scooting around a flat concrete floor in a controlled environment is completely different from a car driving on real roads, and b) if they're ready to start full-size tests in these adverse conditions then they must think they're pretty darn close to having a viable product, given the possible consequences of failure. It's not like they haven't already done a massive amount of R&D to get to this point.
Again, I don't see your point. Before selling a self-driving car product intended to work reliably in X conditions, you have to test prototypes and eventually the production model "release candidate" in X conditions. I feel like you're trying too hard to find a cynical angle on this.
