Clearly, manned vehicles demand a higher level of reliability than cargo carriers. However spaceflight even after decades of experience is still pretty risky. From a life safety perspective, non-manned, robotic missions are preferable. But our drive as a species to explore and populate new territories means that we'll need vehicles safe enough to travel in, and/or people who want to do it regardless of the risk. 1/18 is still probably decent odds compared to the ones facing people 300 years ago, who set out in wooden sailing ships to explore the unknown.