Maybe...you are thinking too much out of the box. A strategic agreement is not something which can be compared to a salesman. It takes years to draft it and wide range of consultations between the top bureaucrats and diplomats of both the countries will take place before entering into it. India and Russia had previously signed one agreement which has expired. Then it was renewed again for 10 more years. [I'm searching for a link for this and hopefully will provide you with one.]
If Russia had even the slightest amount of skepticism, it would not let India lay it's hand on it's most secret military technologies in Russia's arsenal. Like the 5th gen fighters, nuclear submarines, aircraft carriers, long range bombers, missiles, air defence systems etc etc. There is no other country in this would which Russia is willing to share it's technology with at this scale. Now...it's not a minor thing. Even Uncle Sam will not depart with his most sensitive technologies even to countries like Israel or UK. Russia now sees India as an equal..not just a country to whom they can sell their stuff to. From buyer seller the relation has grown towards joint ventures...that my friend...is a remarkable evidence that the changing equations wont hamper the relationship. The relationship of India and Russia has stood the test of time and at a time when both the economies are robust and at a time when India is making it's presence felt on the world stage and Russia slowly crawling back to it's super power status, India-Russia are not stupids to let go of each other!
Now coming to the issue of USA, India has time and again snubbed the US and Russia is clearly watching this. Be it the issue of Iran or MMRCA etc..India has been and will be cautious of US's ulterior motives and make no mistake about it...Indian diplomats and policy makers very vary about US and we know when to butter and when to snub.