While this blog post is much better than most, there is a huge market for "how to be successful, be good at business, etc" and a lot of it is misguided, empty motivational speeches, or hand waviness. There's a lot of survivorship bias and fluff. You can spend a lot of time and money you could otherwise spend on making a better product.

So I don't see the response as the mentality of failure, but more of a warning about the "How to Be Successful" market that's out there. While I agree poor execution is abundant, I think "hard work, contacts and luck leads to success" is spot on. A lot of timing is just luck. If I could perfectly execute a model-T or Amazon.com its doubtful I will be successful because that's yesterday's problem and being first to market has many advantages.