While I understand his reasoning, there are a couple of flaws with it.
When I used to study economics, the models seemed pretty straightforward, but they were based on “perfect” market knowledge, easy entry and exit, and the idea that people act rationally. As I’ve talked about before, people quite often act irrationally. The software market does, in most cases, provide easy entry and exit (with some notable exceptions such as operating systems), but market knowledge is often hard to come by.
With a commodity like corn, it doesn’t really matter if the corn comes from Iowa or Nebraska – corn is corn. But what about cars? Is a Lexus the same as a Mercedes? How about a Hyundai?
The same issue exists in software. Is Tivoli better than OpenView? How can one objectively compare them? Often the comparison comes down to price – with the higher priced software considered “better”. One reason that Micromuse was so successful was that their software was priced higher than anything comparable on the market (at the time) and people just thought it must be better. It’s a problem we run into with OpenNMS – many people in decision making positions don’t think that “free” can be good.
Where I think esr misses the point is that the GPL guarantees a certain level of market knowledge. Without it, someone could take a project like OpenNMS, slap a prettier GUI on it and turn around and sell it as a commercial product. The potential buyer wouldn’t have to be told that there was an open source alternative, and thus the market wouldn’t “punish” the closed source version.
The GPL not only prevents that but provides for severe penalties if the license is violated. Any revenues from such commercial software sold in violation of the license could be forfeit.
To me the GPL is like locks on cars. They don’t keep a determined thief out, but they help keep honest people honest. It is a commitment to keeping the work of the community truly open. Until the software market can be better educated on the value of open source software, it can’t operate efficiently to punish the closed alternatives, so the GPL and similar licenses are the best things we have to insure that the value created by open source communities is protected.