Just like Microsoft there are parts of the company who are hostile to open source, and there parts of the company whose success is attributable to open source.
Apple cooperates within WebKit well with WebKitGtk. They supported LLVM when it is in their interest.
Chrome is used as proprietary web-engine to vendor lock-in the web. While often used by others, I’m not aware of a broad cooperation. Android is a shadow of Linux, merely using the Linux-Kernel, not GNU. Plus a lot of closed-source code (PlayServices, App Signatures, Google Cloud, Google Apps).
Googles open-source projects seem often exclusive Google only projects? Google works together with others! But especially Chrome and AOSP are…causing worries.
This is about whether they contribute to open source or not.
Swift is OSS, but it's not a great example to illustrate your point.
Darwin’s underlying code was BSD license and didn’t require releasing source code.
