India begged the USA to help them in 1962, but what happened then?
India pleaded for US help against China in 1962 - Times Of India
In 1962, the USA was
openly our enemy. We had just previously fought a direct war with them (Korean War). The USSR was also our enemy at that point, due to the Sino-Soviet split.
Not to mention that we were just coming out of the worst famine in our history (1959-1961) and at our weakest possible point.
Today though... Russia is our strategic partner, and we have the largest bilateral economic relationship in the world with the USA, to the point where they were even proposing a "G-2" with us.
All the factors have turned in our favour since 1962. The gap has become so large that the Indian Armed Forces themselves have admitted that: "India cannot hope to match China. The gap is too wide, and is growing wider every day".