Apparently, ESR thinks the GPL is not needed anymore. (For those who don’t follow this type of thing, ESR is Eric Raymond, founder of the Open Source Initiative.) He cites Linux as an example of a project that he thinks would have grown even without the GPL.
He’s probably right about Linux. Linux could have become a big success even without the GPL. However, paricularly as the number of devices using Linux increases, the fact that Linux is licensed under the GPL helps in getting more code out in the open. Consider the Linksys router I’m using. If Linux was BSD-licensed, what are the odds that Linksys would have released their code? What are the odds that we would have alternative firmware implementations that provide more features?
The GPL (or at least the ideas embodied in it) also enabled the dual-licensing model, which is a great boon for some businesses. Consider how few people would buy QT if it were BSD-licensed?
The GPL is one choice in many licensing options. For people who have a project that they want licensed that way, I think it’s good to have that choice. The Creative Commons folks recognized the value there when they created the ShareAlike license.
ESR argues that because open source is a superior way to produce software, the GPL is unnecessary because the open source version of a product will be better than a closed-source fork. I think this falls over with the initial premise that open source is superior. For many types of projects, the open source versions have inferior usability and inferior marketing.
If the ecosystem is built up to the point that open source versions are genuinely, consistently better than their closed source counterparts, then I’d agree with ESR’s argument that the GPL is unnecessary.