Regarding the 5% number, it might be closer to 20%. We spend more time reading about tools that benefit technologists than strategies that create value and convert into paying customers.
Most startups don't solve technically complex problems, except how the technologists are making their own lives easier through the latest language, tool or framework.
Building a project is different than a product. A product is not just the code. We see proof of marketing ruling with garbage products getting into customers hands and they have no idea of better solutions that are available.
The most important part of this journey is absolutely finding the customer, finding their need that they're willing to pay for, finding how to reach them, and then part addressing their need through code.
You need all of those to have a business that makes money, other wise you have a project you want to try to make money with, not a strategic approach to establishing a business.
Focusing on making money is terrifying to too many technologists. The only way you get there is realizing the product itself is 20% of your business and you will inevitably spend 80% of your time learning to get it traction and paying customers. Of course, it's easy to just code some more to add some "value". If that value doesn't reach customers, it's not realized value, just more potential that will sink.
I agree with the entire article except for the last point: read everything possible.
It's an epic waste of time to read about things in detail that you aren't looking to implement right away. Reading articles, especially if you don't end up acting on them is too often a waste of time because you have to come back to them later and re-read when you're ready to do something with them.
I use a slight tweak on the rule: Only read in detail what I need to do right now, or my next step. Only read things in general to understand where I am on the overall project.