I really think this was the FSF's fault - they insisted on copyright assignment for any contributions to GNU, because if the FSF held the entire copyright, they'd be in a better place to pursue legal action against violators. But history has shown that this clearly hasn't been required: Linux doesn't have this policy, and no Linux enforcement case has ever failed because the Linux Foundation wasn't able to demonstrate clear standing. And the FSF basically legitimized everyone else asking for CLAs. Had they stood firm and said that giving up ownership of your code to a central entity is antithetical to the spirit of free software, and the license is all that people can rely on, I think we would have been in a much better place today.