"and a failure of teachers to make the course interesting"
I think part of it is the curriculum being watered down to the lowest common denominator (so "nobody fails", thus no "damage to self esteem") to the point where many students are just plain bored silly. If a student is capable of learning faster, and wants to learn faster than the lowest common denominator, well, that just isn't fair! Those kids need to learn to "get with the program", and if it takes doping them up on Ritalin, etc., well that's what it takes.
While there are legit cases of ADHD (diagnosed by real doctors, not educrats and zampolits), it is nowhere near the level described in the media as far as real cases. Ritalin is to many times just automatically prescribed by the educrat (Why are educrats prescribing drugs? That's a whole 'nuther thread.) as a cop-out. To solve this particular "cause" of "ADHD" is not to throw more money into the education system. The solution to this "cause" is to require the teachers and educrats to DO THEIR JOBS! But then, the NEA won't allow that!
The Indian crowd you see in America is not a sample size for India's general populace. The demographics of the country are far too complex to study/draw conclusions from a few immigrants whom you meet in America.
I have Hindu friends whose beef-eating habits go back several generations through the family line, probably all through thousands of years. In fact, several of them were extreme conservatives, who attributed eating beef strictly according to the Vedas that I mentioned earlier. You can run a Google® search on this fact.