There's an uncanny element to the writing here, but my bigger thing is that it's presenting a sort linear progression to stages of life and startup operating, and saying 36-42 are strong ages for doing startup work, but 42 is the last of those years and 51 is past it: no? An unsupported claim? There are ways in which it is much harder to do a startup at 36 than 51.

It seems clear why 20-somethings have advantages, but extrapolating that out is I think a mistake.

I also think subheds like "Naive Conviction" and "Capitalized Execution" and "Durable Craft" are going to set people off, and as a bit of writing advice I'd avoid them, along with constructions like "It's not X. It's Y." or "X isn't Z. Y is." It's also kind of not-great writing? It starts to sound like something written for Bill Shatner to read.

I'm not convinced of the linearity of this. Consider that Ray Kroc started McDonalds when he was 50.