This advice may be reliably true but I would also argue there are major exceptions. For example, take founder & ceo of any billion dollar company and you will find that they evolved drastically (in good and bad ways) over the years. Zuckerberg has radically transformed himself from an immature frat boy to a charitable, intelligent billionaire CEO. I am sure people who have known him over some period of time would disagree with your investor's line of thinking.