Yes they play very well and work hard and struggle in all matches. Yes you are right because they work hard in all the matches due to which they get very tired.
Yes, because one match schedule ends, another schedule comes out due to which they cannot get rest.Yes, Virat Kholi, RK Rahul, Rohit Sharma, there are players who have made India proud.
All the players from all the countries we have seen those countries that are qualified were played amazingly. Specially the struggle of South Africa we have seen was amazing and the Team Afghanistan is stepping forwards towards their better play and that is the reason they are have some good players now. And also if we talk about the Finalist Indian team also played well regarding to their players they hits most sixes as Rohit Sharma is an example for the World.
And finally the winner of the World Cup Australia was too good on their final day at India, but may be they have new players now in the t20 series against India that's why they lost some matches against them.