It's much, much more nuanced than that.

On one hand, it's very good advice to be clear about PMF. If you have to ask your product doesn't have it. It'll be servers-on-fire obvious when you reach product-market-fit.

On the other hand two things stick out: 1) for every example that proves polishing doesn't matter, there's a successful exception that broke every rule and succeeded anyway. The founder of Figma for example, said he worked on its foundation for something like 4 years before launching. 2) Internet, consumer tech, mobile, sass are all mature markets and the quality bar is very high at this point. It's not obvious that some novel concept will be enough to overcome sheer inertia of status-quo incumbents.