Containment is not a one shot game, its a continuing exercise. How do you think China has been contained? And what will be the relative strengths of the two countries 25 years later? Can US go it alone in Asia against China? If not, then besides Japan which is the other big country which can substantially oppose China.
US will always like to play the puppet master game rather than getting into direct conflict. Why else do you think the new found keenness for defense ties? OK, sale of arms is one factor but not the entire story.
As for tech, money and educations, we don't need a defense tie to get those.
Problem is that Russia is of no help when it comes to opposing China. That's where US scores. Recent Chinese incursions have made India look for defense partners.
China has been contained in pretty much the same way India had/has been contained i.e. building a global consensus against them.
India has been denied access to technology and money and was subject to discriminatory trade practices by the US. 60+ years after independence ware are still a developing nation. If that is not successful containment by the US, I don't know what is.
The only reason US has decided to engage us is because we have successfully built Nukes (thermonuclear too) against all odds and have successfully built a Missile that can reach US. If you look back in the past you will see that this was the same strategy the US adopted to engage with China once they too became fully nuclear and built missile that could reach US. (read up on kissinger first contact with china)
Its just history repeating itself, only we are just not as driven as China in nation building nor as stable as China, to take full advantage of our US engagement.
Even 25 years down the line I do not expect China to be able to build enough goodwill and influence globally to successfully turn the tables against US. For China to do that, it must first unshackle its own society and learn how to engage its own society in a free world.
US has shown enough guts to directly get into conflict for the past 70 years starting from World war, Europe, south Korea, Vietnam, Africa, south America, Israel, Iraq, Afghanistan etc. Do you realize how absurd you sound when you say US does not directly enter conflict.
Even today US is mastering UAV technologies and AMD that will ensure minimal dangers to their armed forces and civilians.
Our engagement with the US is not defense ties, but an engagement where each party seeks what they need. That is the normal way in which any engagement takes place.
Himalayas are still the greatest barriers to any Chinese invasion than any US friendship. That and our own significant Armed forces. The whole world including China knows this.
Our greatest potential enemy continues to be the US which is why it is so important that we engage with it rather than sulk in the corner.