Sure! The idea is that each proprietary project is wasting effort implementing their own clones of everyone else's software. To use your example, Google, Microsoft, Yahoo, Yandex etc etc are all developing their own search engines. Instead they could all be contributing to one search engine to push the state of search engine software forward, instead of all spinning their wheels re-doing what everyone else is doing. How many devs are employed doing what someone else in some other company has already done? That's the broken window: someone else has already done the work, but it must be wastefully re-done because of the license. There's a lot of room for profit in all that extra waste.

Aside from whether this matches the typical meaning of "broken window fallacy," I think the substance of what you're saying doesn't match reality.

Open source is famous for fostering a bunch of different approaches to the same problem, and slightly different forks of the same concept. That's the "bazaar" in the famous metaphor, as opposed to the "cathedral" of monolithic, hierarchical, linear proprietary development within a closed-source company.

"Everyone working on the same thing" only works well when there is broad agreement on what that thing should be, and strong governance to resolve disputes. National highway systems, militaries, and power grids are good examples.

I don't think search engines are a good example of where this would work; it's not clear in advance what will make a given search engine better. Thus we benefit from a variety of competing approaches, essentially to expand the space in which we're searching for the optimum.

That's not what the broken window fallacy is though. It references the idea that breaking a window generates economic activity which is good for everyone.

Open source software is (I would argue) even more driven to fragmentation by political, ideological, and personality conflict driven squabbles than proprietary software, as there is no profit motive to also satisfy.

Also, the broken window thing asserts that small amounts of criminal activity lead to larger amounts of criminal activity via signaling that being bad or neglectful is OK, which is both not proven and irrelevant to software writers being prone to reinvent the wheel for whatever reasons they have.

You're describing the broken windows theory. The broken window fallacy is the claim that destruction or waste is good for the economy because the cleanup generates economic activity (with the attendant multipliers). It's a fallacy because it leaves out that the original spender (by the owner of the broken window), on average, displaced other economic activity.

While I'm no fan of these companies, I'm not convinced by that particular argument for FOSS either. Imagine the world where we would be always iterating on one lineage/model of refrigerator, each automobile type etc. instead of many companies rebuilding basic stuff. I don't believe we would be better off. Not all progress can be driven by consensus and iteration, some needs to be done by competition, divergence and outright discontinuing old approaches.

Thanks for the elaboration.

I think you would be right about the greater good being served by everyone being aligned on the same search engine ONLY IF we understood search engines so well that we knew there to be only one mathematically optimal way to build search engines.

Since we don't understand search engines that well, there is a LOT of value in the exploration over the space of search engines that these different companies represent.

The broken window fallacy argument is that those speaking of the benefits of the broken window are mistaking maintenance cost for generated value. That doesn't seem to be the case here. This is society implicitly investing in exploration over exploitation.

Well, in reality there wouldn't be one optimal product, there would be many, for the reason that you said -and for human reasons.

However they would still be able to borrow good bits from each other and gain insight on how things could be done differently, so arguably the end result would be a win. From a technical standpoint that is -I think where it gets messy is when we try to factor in the business implications.