It was not a bad luck rather Indian team was not well prepared for this mega event. India, NZ and Pakistan need to win at least one match against each other to stay in the tournament but India lost both with huge margins. It's not justified to analyze Indian team performance based on their performance against Afghanistan, Namibia and scotland.
Indian players have the advantage of playing in the richest franchise T20 league in the world. But they still couldn't manage to qualify for the semi-finals. I have a feeling that the BCCI is wrong when they are banning all the Indian players from participating in foreign T20 leagues. There is no justification to do that, when foreigners are taking part in the IPL. At least those who are not part of the Indian squad should be allowed to play in the foreign leagues. This sort of monopolistic tendencies will do more harm in the long run.