U.S. pivot towards India began after 9/11 and that included containment of China as well as bringing Pakistan into Indian orbit. The gas pipeline deals TAPI was primarily for Indian benefit where Afghanistan and Pakistan were happy surrogates and access points to central Asia. Since Pakistan didn't comply and arm twisting didn't yield much benefit it has shifted to a more long term plan B and that is to stifle Pakistan and bring it to its knees by internal strife and economic meltdown. By offering F-16s to India U.S. has given Pakistan a no uncertain answer in whose side U.S. really is and that effectively leaves these planes redundant if India goes with it because of better technology for India and no spares for Pakistan. U.S. had started a very ambitious policy of propping up India in last decade by billions in investment and off shoring of high end jobs. That India is a reluctant ally is Indian psychy which doubts the end result. Next few years will be firming of India as an ally which Clinton had already started as secretary of state by a speech few years back. Trump in my opinion has been a pumpkin that put outside the door with a scary face for Halloween to show what could be yet discard in trash the day after.