Actually I believe that the Series might have been fixed. I also believed the same when India toured Pakistan. The matches were fixed to allow the visiting side to win so peace talks etc. would go well. This might not be true, but losing 4 consecutive ODIs at home dosen't sound right. They got out throwing their wickets away. Then again, it might have happened(we all know how corrupted the Indian government is). Players like Dravid, Kaif, Sachin and Dhoni probably didn't get bribed as they have been servicing Indian cricket for a long time(except Dhoni , who was quite new). Kaif played well, so he couldn't have been bribed. The matchfixing might have occured after the first 2 ODIs as India was winning.
Remember, all I am saying is that this might have happpened in the last two India-Pakistan tours.