The context of when the book was written has more to do with it—at a time when startups didn't have access to the great SaaS tools we have today. Now, you can

The context of when the book was written has more to do with it—at a time when startups didn't have access to the great SaaS tools we have today. Now, you can start and scale a business with just 1 or 2 people to the point of "product market fit" simply by using more specialized software. You don't have to brute force as much of the initial stage compared to the time the book was published, where "pivoting" was more uncomfortable (i.e.: sunk cost fallacy).