One stat tells the whole story:
There have been nine 50-plus scores in the series for each team. Australia's four best scores, though, are 329*, 180, 150* and 134. India's top four scores are 83, 80, 75, and 73.
In the last 13 months, India have lost five Tests by an innings: one in South Africa, and two each in England and Australia ... Between October 2001 and March 2008 India didn't lose a single Test by an innings.
The Indians simply don't have the bowlers who can contain the English and Aussie batsmen. End result: innings defeats.