Because it’s a great idea but for instance the Linux kernel would have to come with documentation that mentions the tens of thousands of authors. A massive undertaking that doesn’t help anyone, really.
> Linux is GPL and I doubt it would have tens of thousands of authors if it were not.
Why? There's plenty of permissive F/OSS projects with large numbers of contributors.
> It would have a dozen proprietary forks.
Probably, but proprietary forks don't stop F/OSS contributions. They can even be the source of them, as upstreaming everything that isn't secret sauce reduced the cost of maintaining the proprietary fork. A number of the big sources of F/OSS contributions to Postgres are maintainers of proprietary downstream distributions (I don't know that all are strictly forks, since I think the proprietary bits of at least some are using the extension mechanism.)
> Why? There's plenty of permissive F/OSS projects with large numbers of contributors.
Companies invest in developing Linux to create a commodity they can leverage to sell their products and services. The GPL ensures the investment remains a commodity and cannot be used in proprietary products that can't be also leveraged by the initial contributor.
There was a lot of BSD in the core of every proprietary Unix, each tied to a given manufacturer.
> There was a lot of BSD in the core of every proprietary Unix, each tied to a given manufacturer
Except MacOS X, the major proprietary Unixes all predated permissively-licensed releases of BSD, and the early permissively licensed releases were under a copyright cloud for years that prevented anyone from relying on them for commercial downstream distributions.
Documentation is not the problem. The problem is that, the advertising clause requires ALL promotional materials to include these acknowledgements, for ALL software that has been used in the software. It was not a problem for BSD back then, since UCB was the only developer. But for projects with multiple copyright owners, such as the Linux kernel, a Linux distro poster would contain a thousand lines of acknowledgements, and this is not even counting the packages in the userspace.
A modern revisiting would probably require crediting the project as a whole rather than each individual author, and maybe have separate consideration for products that derive from a large number of such projects.
The primary problem is that 4-clause BSD is incompatible with the GPL since it adds restrictions to distributing the software (notably the advertising clause)
This license is also sometimes called the “4-clause BSD license”.
This is a lax, permissive non-copyleft free software license with a serious flaw: the “obnoxious BSD advertising clause”. The flaw is not fatal; that is, it does not render the software nonfree. But it does cause practical problems, including incompatibility with the GNU GPL.
The Flowplayer Free version is released under the GNU GENERAL PUBLIC LICENSE Version 3 (GPL).
The GPL requires that you not remove the Flowplayer logo and copyright notices from the user interface. See section 5.d below.
You may convey a work based on the Program, or the modifications to produce it from the Program, in the form of source code under the terms of section 4, provided that you also meet all of these conditions:
* If the work has interactive user interfaces, each must display Appropriate Legal Notices;
