On the other hand, there are plenty of people who worked hard and still failed in business due to bad luck. This article is pure fluff.
In less saturated markets being competent and working hard enough to sell might be enough.
However, this skill cannot be taught, cannot be honed, etc.
What can be taught or practiced, at least partially, is the ability to be prepared for serendipity.
You're absolutely right though, and plenty of people fail for many reasons including bad luck or for reasons they had no control over. As a society, we need to make sure that folks who do take a a chance but fail aren't left to rot and still are able to put food on the table and take care of their families.