OK, but ... imagine Andreessen said, "I don't eat food."

No one would think that was a reasonable position.

No one would argue, "Well, food DOES have draw backs. What if you eat too much of it!"

We all inherently understand that you have to eat food, and while being careful not to eat too much.

We would understand that if anyone said, "Look at all these successful people who also didn't eat food!" that they were talking absolute shite.

No one would treat the statement "I don't eat food" as anything other than deeply fucking weird.

I feel like your comment is evidence that you are insufficiently acquainted with various flavors of cult-like behavior and wingnuttery. There are in fact people who sincerely believe that you don't have to eat [1], who believe it so fervently that they risk and sometimes lose their lives for that belief.

Humans are social creatures. We are biologically inclined to follow charismatic leaders, even off a cliff. In most people, the susceptibility to suggestion is much stronger than the strength of their rational beliefs. Just look at American politics, for example.

All of this is to say that if Andreessen said, "I don't eat food," there would be a small but vocal group who would see that as validation of their beliefs; there would be a think-piece in the Atlantic about the history of breatharianism; Hacker News comments about what does "food" mean, really, etc. Yes, people would take it seriously. Just because he's rich and has therefore bought a loud megaphone.

[1] https://en.wikipedia.org/wiki/Inedia

Are you kidding? People would eat that up if he said that. Soylent would sell like crazy. You'd see protein smoothie shops pop up all over the bay area. For better or worse there is a subset of people who just lap up at whatever comes out of these people's mouth.