alt Hacker NewsSeems to be anti-pattern #4: If you build it, they will come. His description matches yours almost word for word.
> The founders automatically assumed that if they had the vision and one customer wanted it, many others would
https://www.itamarnovick.com/startup-anti-pattern-4-if-you-b...
FWIW I think it is miscategorized. "Build it and they will come" is a different type of problem: it commonly refers to building something thinking that its value and usefulness are self-evident that it will sell itself, and therefore one needs no sales or marketing.