Of course, more companies contribute back to Linux than contribute back to FreeBSD; they're obligated to. I don't think it's as simple as that. The license has

Of course, more companies contribute back to Linux than contribute back to FreeBSD; they're obligated to. I don't think it's as simple as that. The license has a major influence on the ecosystem around the project, and it is that ecosystem that determines the contributions that flow back to the open source code. The GPL encourages a certain type of ecosystem, and BSD another; that the GPL will automatically yield a healthier ecosystem than BSD is not at all obvious to me. One of the major differences is that with the BSD license, companies are free to build proprietary products on top of the open source code, which opens up a lot of business models that aren't feasible with the GPL. Take Postgres, for example -- there are many companies that have used Postgres to build a proprietary database of some description. Some of these companies choose to contribute changes back, or to employ Postgres developers full-time, or to hire them as consultants -- mandating that all changes be contributed back would probably mean the companies wouldn't exist in the first place, or wouldn't be using Postgres, which would probably be a net loss for the project. And if a company chooses not to contribute code back? Well, personally that's fine with me, but I can understand why others might disagree.