One thing many people think the traditional mode buys you is somebody to hold legally liable and potentially recover compensation from if the project goes wrong. But this is an illusion; most software licenses are written to disclaim even warranty of merchantability, let alone performance-and cases of successful recovery for software nonperformance are vanishingly rare. Even if they were common, feeling comforted by having somebody to sue would be missing the point. You didn't want to be in a lawsuit; you wanted working software.
So what is all that management overhead buying?
In order to understand that, we need to understand what software development managers believe they do. A woman I know who seems to be very good at this job says software project management has five functions:
To define goals and keep everybody pointed in the same direction To monitor and make sure crucial details don't get skipped To motivate people to do boring but necessary drudgework To organize the deployment of people for best productivity To marshal resources needed to sustain the project
Apparently worthy goals, all of these; but under the open-source model, and in its surrounding social context, they can begin to seem strangely irrelevant. We'll take them in reverse order.
My friend reports that a lot of resource marshalling is basically defensive; once you have your people and machines and office space, you have to defend them from peer managers competing for the same resources, and from higher-ups trying to allocate the most efficient use of a limited pool.
But open-source developers are volunteers, self-selected for both interest and ability to contribute to the projects they work on (and this remains generally true even when they are being paid a salary to hack open source.) The volunteer ethos tends to take care of the `attack' side of resource-marshalling automatically; people bring their own resources to the table. And there is little or no need for a manager to `play defense' in the conventional sense.
Anyway, in a world of cheap PCs and fast Internet links, we find pretty consistently that the only really limiting resource is skilled attention. Open-source projects, when they founder, essentially never do so for want of machines or links or office space; they die only when the developers themselves lose interest.
That being the case, it's doubly important that open-source hackers organize themselves for maximum productivity by self-selection-and the social milieu selects ruthlessly for competence. My friend, familiar with both the open-source world and large closed projects, believes that open source has been successful partly because its culture only accepts the most talented 5% or so of the programming population. She spends most of her time organizing the deployment of the other 95%, and has thus observed first-hand the well-known variance of a factor of one hundred in productivity between the most able programmers and the merely competent.
The size of that variance has always raised an awkward question: would individual projects, and the field as a whole, be better off without more than 50% of the least able in it? Thoughtful managers have understood for a long time that if conventional software management's only function were to convert the least able from a net loss to a marginal win, the game might not be worth the candle.
The success of the open-source community sharpens this question considerably, by providing hard evidence that it is often cheaper and more effective to recruit self-selected volunteers from the Internet than it is to manage buildings full of people who would rather be doing something else.
Which brings us neatly to the question of motivation. An equivalent and often-heard way to state my friend's point is that traditional development management is a necessary compensation for poorly motivated programmers who would not otherwise turn out good work.
This answer usually travels with a claim that the open-source community can only be relied on only to do work that is `sexy' or technically sweet; anything else will be left undone (or done only poorly) unless it's churned out by money-motivated cubicle peons with managers cracking whips over them. I address the psychological and social reasons for being skeptical of this claim in Homesteading the Noosphere. For present purposes, however, I think it's more interesting to point out the implications of accepting it as true.