Across 5 funding rounds, Crunchbase lists Loopt as having raised $39 million and then was acquired (acqui-hired?) for $43 million. He didn't create any multiples of value for his investors. Loopt wasn't a breakout hit like so many other YC startups have been. It was certainly one of the first interesting location-based apps in the App Store, but soon was surrounded by other location-based apps and never really appeared to surface and gain traction.
Obviously Sam runs YC now and has dramatically improved it, but in the lens of being an entrepreneur, isn't he still essentially unproven, and not a success story in the startup world?
From first principles, if you were looking for someone to give startup advice, then you want someone who has: been through the process; doesn't suffer from survival bias which just elevates all the random things they did and weird habits they have to some kind of mystical formula; has seen many other people go through the process from the very early to late stages. That's why you should listen to Sam Altman. If you want to worship mega-entrepeneurs then there are many other avenues for that activity.