GCC and LLVM - What's in a licence? (ITPro)

One of the most important attributes of the larger BSD (or GPL) licensed projects (those with sufficient critical mass) is that future contributions back to the original codebase are encouraged by the long term support costs/issues. The free software projects provide an ongoing support mechanism that is commercially fairly costly. So, forking a project like LLVM for 'selfish gains' can be more costly than if the work is fed back to the original project, even if very freely licensed like BSDL. The costs of long term commercial support of a highly forked project equivalent to a non-GPL GCC, would likely outweigh any benefit. A 'wise' business person will most likely feed back the changes. The same is true for LLVM. On smaller projects, with less of a central critical mass, this argument is not quite so convincing.

So, BSDL software does not have to depend upon altruism, because feeding back changes to the original development can quite often have a selfish benefit. In the case of (at least) GPLv2, there is no legal requirement that I know of that the changes be fed back to the mainline tree, but that those who receive binaries also have bona fide access to the source. On the other hand, both BSDL and GPL software have the 'selfish' support cost motive to feed back substantial improvements.