Its a matter of luck? Not all of it. Its the level of uncertainty in the whole process that makes people believe that it is a game of chance or a matter of luck etc. To prove this point, meet 3 civil servants of the same batch and ask them the criteria. One will say that it all depends on your score in written part, the other one will assert that psychological assessment leaves a better impression of the candidate, and yet there will be another one who will point out viva as the real game changer. So where actually is decided that a candidate is good enough or not no body can surely say. This is where "CSS is a game of luck" thing comes into play. If that ambiguity is removed and everything is made crystal clear, luck will have lesser say in this and hardwork will be the real criteria for success.