Everyone is to take the blame. Players, coaches, selectors, management and even the fans and critics.
I thought India as always were a bit over-rated going into the World Cup. I thought there were four teams more likely, capable and deserved of winning the competition. This hype is generated by the media and the fans and puts additional pressure on the players. Two good home ODI series wins over SL and WI cannot undo India's horrible form outside the subcontinent.
Obviously I had expected India to enter the super 8s but had also said that Bangladesh were the most likely team to cause an upset. On their day they can match one of the bigger sides.
Also there are a lot of posts saying X,Y,Z should have been selected. But I dont think there is any player who would have made any drastic difference to the Indian side. If those players had played and lost the game then many would question the absence of the current players.