And to bolster your point, people like Huang are surrounded by yes-men constantly. When you are a nobody, people criticize and keep you in line. Once you're running NVIDIA, people want power/money themselves, so they will tend to grovel and supplicate. Eventually, even the humblest begin to believe their own PR.

Those are "external influences", but your own gravitational field has warped them. Even the president wants your money and influence, and needs your company to do well, there is literally no one who will "give it to you straight", and it warps your mind.

The Roman commanders would sometimes hire someone to stand behind them and remind them they were only human for this reason (to avoid natural hubris), it was seen as naturally arising in these circumstances, and needed to be combatted to remain effective.