If you are starting a startup and have no money to burn through validating a business model, your only real way forward is to start with sales. You can sell your idea to potential customers (bootstrapping), or you can sell it to investors.
There's no third way to do this, because those are the only two groups of people that can give you money.
This guy is choosing to bootstrap. A fine path, but it requires you to schlep. You have to talk to a lot of people to validate a business idea. People who are so enthusiastic about the idea suddenly develop cold feet when it comes to buying your product and integrating it into their business / life.
If you are a coder, the natural tendency is to avoid talking to people and instead do what you know: build product. But unless you talk to people you aren't going to know what to build. His entire blog post is just exploring these failure modes, except with added self-importance.
"... no conclusions to share with you at this time, as Iām still trying to find my way"