Which is amazing but irrelevant - if the lesson is "build something obsessively for years until you have an audience to then, also over the course of 4 years, monetize on another project - assuming you get both of these things exactly right even though they're both unbelievably hard" there's no lesson.

I know this from experience. I helped build a site used by millions of people in a particular demographic, and some of my collaborators on that project have been building products to help that demographic in deeper ways. The problem? It's still hard to get that right! 2 years into that effort they're still just starting to find product market fit for the second products.

We hit the absolute lottery to somehow get 5 million users for the original product, and they'll be hitting the lottery again if they get profitable on the second product to that audience. It's hard. Having money helps.