Even more than that. Most of the Silicon Valley employees of Apple do not work in either the Spaceship or any of the Infinite Loop locations. There are dozens of buildings around Cupertino and Sunnyvale (many quite large) that house Apple employees. If you just drive down Deanza Blvd you will see Apple sign after Apple sign pointing out those builds (and that is just one street).

Yes, it does actually surprise me that a company would spend $5 billion for and tout the design as the second coming of office Jesus as an "incremental office build".

I indeed did not realize that Apple Park wasn't the primary office building in that area, especially because of some of the articles that came out at the time. It's why I asked the honest question I did.