The scorecards seem to suggest otherwise, Between 2010-2012 India played 35 Test matches. Dhoni played in 33 matches, Tendulkar 32, Sehwag 30, Dravid 27 and Laxman 26. Over this period, they played 19 matches away from home, of which Dravid appeared in all 19, Laxman played in 18, Dhoni 17, Tendulkar 16 and Sehwag 14.
As mentioned earlier in the thread, India have been almost unbeatable at home, so it is clear that the talent is there within the team. The problem is they are exceptionally poor when playing away from home and a large part of that is due to the ineffeciency of their spinners.
One of the reasons why things have been a little dire for India as of last is that they have yet to play a home Test match since November 2013. Their last 15 Test matches have all been played away from home.
In 27 innings over this period, India's bowlers have allowed 8 scores of 500+ and 7 scores of 300+. They have bowled a team out for under 200 just 3 times. When teams are scoring 300+ 56% of the time they bat, you are going to have a hard time competing in games consistently, let alone winning.
Just to dig deeper into this, India have been especially bad in the opposing teams first innings, allowing 7 scores of 500+ and 4 scores of 300+ in 15 innings. They have bowled teams out for under 250 just 3 times. Opposing teams average first innings total is 415.93.
To put this into context, away teams conceeding 400+ runs in the first innings of a Test have won just 5.12% of all matches played in the history of the game. I went back and painstakingly dug through every scorecard; there have 684 instances where home teams scored at least 400 runs in their first innings. These teams have gone on to win 380 matches, drawn 268 and lost just 35. There was also one tie in there for good measure (
West Indies vs Australia in 1960
). As you can see, their bowlers are just not giving the team a chance to win away from home.
I would also argue that 5 years is not a slump but a trend. This is not a knock on India, this applies to all teams in Test cricket. Winning matches away from home in recent years has become increasingly difficult; South Africa are the only team with a winning away record over this period.