They probably noticed that Moscow was financing the Muslims causing all the horror in India's border disputes with Pakistan.
Of course, I'm sure the lucrative outsourcing contracts with American businesses didn't hurt either.
Russia still remains important for India,if not more important than the US when it comes to arms purchases.There is still a lack of mutual trust between New Delhi & Washington on numerous issues.If you've forgotten, US-Russia ties have also got progressively better since the Cold War,so I don't see this playing out as India divorcing from Moscow.
Russia never financed any of the Slammics being sent in from Pakistan(one American ALLY)-those folks recieve funds from places like Saudi Arabia & the UAE(2 other American ALLIES!!).If anything,the same terrorists who enter into India,also pay routine pilgrimages to Chechnya.The Russians have desisted from selling any arms to the Pakis,despite Chinese pressure.If you look at the weapon systems sold to India & China,you will realise that India always gets ones which are technologically advanced.