Shri Sankar Ji,
Generally if you notice, its usually the brahmins of tamil nadu and kerala who do very well academically. Probably its not possible to say the same thing when it comes to brahmins of northern india. In the cow belt regions of Bihar and UP, they might seem more endowed with military kind of ability to a layman's eye (thakur type). And one might come across average NB southies who have performed better than brahmins of north india or gujarat or maharashtra.
In Andhra, the rate of brahmins who drop out of school is high, am told their greatest drawback was that they took to english education rather late (and it is unfortunate, because telugu sahitya pundits, poets, etc were almost always brahmins...when the patronage for indigenous arts was gone, their circumstances became difficult).
Unless a child is nurtured, one never knows its full capability. In that way, for many NBs its still the teething stage since they have taken to education only since the post-independence times. i suppose its too early to predict the performance abilites of other communities as yet.
Also, academic performance, focus on marks and getting degrees may not be the main focus of other people. Eg: marwadis like lakshmi mittal or the birlas who run successful companies perhaps have a diff kind of intelligence when it comes to entrepreneurial skills, strategy and finances.
Am not sure if NBs wish to ape Bs. World-over, the focus is now on developing knowledge-based economies. So intellectual capital has become a necessity to make a living for everyone, irrespective of whether they like it or not. Therefore the focus of people is knowledge-building in the present times.
God forbid, if by a strange change of circumstances, a meteor hits earth, financial markets collapse, climatic changes force population displacements and trigger civil wars for water and cultivatable land, then the survivors in such situtions might probably end up being the ones that are physically the sturdiest (like some of the african tribes). And in those circumstances, people might probably like to ape artisans for new city planning / building or military kind of people to keep territorial control and so on...what am saying is that the focus of "needs" of people may change at diff times depending on circumstances or survival means.