There are a dozen articles a month on HN from founders or coders with websites that all say “know your customer before you write a line of code” or “find customers ready to write a check” before you start. “Sift through fool’s gold” - that’s what that advice is helping you avoid, time wasted coding a website that has no business validation. Adding features no one wants.
If the author pushed One Item Store and said “I’m going to market it cause it’s cool now, I’ll add features when people ask for them” then he might enjoy it more and be surprised to find people who will use it and pay for it as is.
GP said nothing about customers. They said to align your work with your life. I'd re-phrase what you said as: align your work with the lives of your customers. That might be fool's gold for somebody, nevermind how many HN posts assume otherwise.
If the author pushed One Item Store and said “I’m going to market it cause it’s cool now, I’ll add features when people ask for them” then he might enjoy it more and be surprised to find people who will use it and pay for it as is.