It's funny, I also read the book as a teen, and I came away from it amazed that IBM was dedicating entire team members to inter-/extra-team communication.
Before that I hadn't even considered how necessary a product manager or project manager were in software development.
But it was the "No Silver Bullet" essay added as a bonus in my copy that I think about the most. "Never again will we see a 10x productivity increase in a decade", this is self-evident now but must have been crushing to people who had experienced the first compilers, the first high-level languages, the first interactive terminals, and waited for the next incredible leap.