I don't mean this as an attack or insult. It just seems to me that people in this sort of situation are very prone to knee-jerk reactions and generalizations that certainly sound good based on their accounts -- and often have some merit -- but that don't quite cover what ought to be the underlying lessons, or take into account larger views that might not fit their argument.
Is it wrong to sell equity? Is it unsustainable, is it fundamentally flawed, is it stupid? No, it's none of these things. It's a specific choice made in specific circumstances that can be good, bad, or (more usually and over the course of time) some combination of degrees between those two virtually worthless extremes.
Is it right to sell products/services? Is it superior, morally, ethically, financially? No. It depends on your business model, your goals, your resources, and a million other things that even themselves vary from situation to situation.
The article isn't bad or wrong. It's just taking a very small view of a very large topic.