Eh. If you talk with second-time founders, a really common theme is how inefficient in retrospect the work-all-the-time phase was and how they want to do it differently.
I don't have a lot of data on current <10 person startups, so maybe it's all different now. But the times I was working 80-100 hour weeks were just not time well spent. It was not, "How can I deliver the most in the time I have?" It was "OMG pressure makes me so anxious I'm going to work all the time to avoid thinking about the stakes." It was more drama than effectiveness.
And people have been saying so for a long time. E.g.: https://lostgarden.home.blog/2008/09/28/rules-of-productivit...