At the user's end, if the neutral conductor is not earthed, there will be no return path for current, and hence no danger to human life. Doesn't this outweigh any benefits of earthing?
If the "neutral" is not earthed then it hasn't been neutralised and it can't be called a neutral anymore. You will have created a floating AC power system.
This will be OK until the first ground fault at which point the other conductor becomes live. As a result you will also have to fuse both conductors rather than just the live in an L-N system.