This is great advice for YC-stage companies. For bigger companies, the biggest challenge is how to continue to focus on the “write code and talk to users” part,

This is great advice for YC-stage companies. For bigger companies, the biggest challenge is how to continue to focus on the “write code and talk to users” part, while having to deal with everything else, which unfortunately becomes harder to ignore as you grow. "Why organizations tend towards inefficiency as they grow" should be a fascinating chapter in the "How things get done" book.