Please do not imply that all IIT and IIM graduates are brilliant. A good number among them are sloggers with just mediocre aptitude.
There is enough evidence for this in many of the companies here in India (and perhaps abroad too). If one gets closely associated with the preparation for entrance to IITs and IIMs, one will realise that there is a lot of room for mediocrity in those institutes (albeit made up with dogged perseverance).
