I have to disagree with the first points: 1. Code is 5% of your business: no, it isn't. If you have a watchmaking company, is making watches 5% of the business? Marketing, sales, and operations are only important as long as you have a quality product. 2. Design is everything: it can used to great advantage, but let's keep it real. There are plenty examples of successful "gray boxes" applications, don't confuse aesthe…
You have to keep in mind that he wrote this after a few years in business. After creating the product, programming takes up less of your time in day to day operations. HelpSpot is business software, and Ian was running it as a one man shop for a while. When you have to do the marketing, customer support, accounting, and, well, everything by yourself, it just plain takes up a lot of your day.
Several points are hit here (some I said in a previous comment): - get to know the customer (build MVP ...), see what they want, make a product not a Software Design masterpiece - prioritize correctly (and oftentimes - especially after you built the product - the biz is more valuable)
Anyway, my experience is that even if one knows this theoretically, he will get it after the practical experience. Good luck building!