You don't have to look beyond Elon Musk to see that the half-crazy ideas are the ones that get people excited. I've been following Zoox since it was literally just a guy with some concept art talking people up in hotel bars at tech conferences. It's in the article, why did Jesse Levinson, cream of the crop in robotics talent decide to go with Zoox and not Google? Because it's an opportunity to really innovate. Zoox has managed to get tons of great people on board for that reason alone.

Otherwise you're right, it's very much an open question as to whether they can make these radically different vehicles to automotive grade reliability.