Yes, some people won't give back. However, a project like llvm/clang, most people do give back because sharing is cool, and also it makes their job easier becau

Yes, some people won't give back. However, a project like llvm/clang, most people do give back because sharing is cool, and also it makes their job easier because they don't have to repatch for every new version of the compiler. Sony's team developing the Playstation 4 wished at times they could use newer versions of llvm/clang for their software, but couldn't because their version had so many patches [1]. Because of this, after the PS4 was released, Sony developers sent a bunch of patches upstream, and work pretty closely with the rest of the developers. Some bits and pieces may not get merged upstream, but that's the same for any project, GPL or not. [1] http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain.pdf http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain....