In 1956 the US signed a friendship treaty with Pakistan leaving India with little option but to sign a friendship treaty with the other camp, the Russians which we did in 1971.
India also wanted the option to license build aircraft, as the first step towards indegenous designs. The Russians were far more willing to let India license build its designs than the Americans ever were! Starting 1965, India was manufacturing the Mig-21, then the top of the line fighter for the Soviets, at Nashik. Doubt if America has ever allowed any of its allies this kind of access.
In any case, military partnerships are built on trust. Americans are far less reliable as military partners. India should stick to tried an tested friends like France and Russia, or else stick to indegenous designs.