Could be a by product of the Green Revolution, increased wealth results in upward mobility. As Punjab became the richest per capita state in India, people tend to shift from Agriculture to Services. As probably the first large scale entrants of any Indian sub-group in the private ecosystem, compared to the fascination with govt jobs of the rest of India, it must’ve been a largely underpenetrated opportunity. It’s simple math that if the entry cohort has a large proportion then, most likely senior leaders will be from that sun-demographic on a pure statistical angle.