Three wickets in just three balls was enough in the end and that's what the New Zealand players did. But if the last wicket Washington was not aggressive and could throw a few overs with strikes, then there might have been some chance of victory. But there too, Washington failed. Basically, it was written in India's fate that India would be whitewashed, that's why India could not beat the target of 147 runs.
I understand your point of view that only if India could have scored 25 more runs, they would not had to face the defeat. But then we can't blame Washington Sundar or Ravichandran Ashwin for not completing the game. These runs should have been scored by the Indian top order and if they failed, we cannot just put all the responsibility on bowlers to do the batting as well.
Also i think that even if the Indian team would have won this match but by losing 8 or 9 wickets, i would not call it a healthy win. Another think that India will be playing a test series against Australia from 22 of this month. Not much time is left in this series and they need to improve this batting.