Regarding lesson 4 (Distribution), the author links to a tweet by Justin Kan saying "First time founders are obsessed with products. Second time founders are obsessed with distribution".

Justin Kan posted[0] today a video of himself criticizing that very tweet, saying that it didn't age well and he now believes product is 99% of the work, and the reason that many unicorns are founded by first-time founders is they don't get distracted by thoughts about anything other than product, like distribution.

[0] https://twitter.com/justinkan/status/1418003365695418373