Nandan Nilekani from Rs 200 to 7,700 crores ?

Nandan Nilekani , the former UIDAI chief and co-founder of Infosys, who has recently joined Congress,disclosed details of his assets while filing his nomination for Lok Sabha.
He recalled when he co-founded Infosys, he had Rs 200 in his pocket and today he has assets worth Rs 7,700 crores !!
But one thing that might be keeping politicians baffled is, if he has already made so much money legitimately, why is he required to join politics ?  😀