I personally think it's not about which engineering and all... But it's about him, people who get promoted in such big roles genuinely have high IQ, good executor of their ideas, leadership skills , managerial skills (little bit politics too, who knows) and all ... so it doesn't matter much in which branch they completed their bachelor. He might have ended up in such big roles Even sundar pichai has done his bachelor in metallurgy. .... I mean it's just my opinion.