That's probably closer to the conventional wisdom around HN, but it is a far cry from conventional wisdom amongst the masses. The wisdom amongst the masses is that if you co-found or join a startup, you are playing roulette with your financial security.
But the article's point -- which I agree with -- is that even if you accelerate this process of getting to that 5 year threshold, you are doing yourself a disservice fiscally by settling in at the plateau unless you have a good reason forcing you into settling.
You're likely still learning more, and becoming more valuable, but it becomes much more difficult to extract that value through salary. So, it becomes beneficial to join companies where that only makes up a part of the total compensation package.