This quote is trashhhh (no offense to the poster)

I don't disagree with the notion that sales can be a very valuable skill, but the idea that "EVERY successful person knows how to sell" is something with which I HIGHLY disagree and that idea is proven false by vast amounts of evidence.

Now, I would allow that maybe the validity my change depending on your interpretation of the word "successful" as that word is somewhat objective. You might have an argument if you subscribe to the juvenile idea that lots o' money is what makes one successful, but it is just that: juvenile.