An interesting article from CNET.com confirms what I always thought of open source: The fact that you have a business based on proprietary software is somewhat orthogonal with the fact that you participate to the open source movement, whether by publishing new code under and open-source license, or by increasing interoperability with existing OSS software. If you look at other companies like Sun and IBM, they are using both the OSS model and the proprietary software model in their products, and for good business reasons. And what I also think is that, fifty years from now, the software world will look pretty similar with today's world, when you have a complex mixture of OSS and proprietary software products. Open source won't necessarily change the way people are doing business. For good or for bad, proprietary software will still be here in the years to come.
True, in the past there was a lot of animosity in the past around this subject, but from what I can see the tension is going down, as many people, especially in the corporate environment, are learning to view the open source community not necessarily as enemies, but more like a natural part of the software world. And not only that, but I also see that a new tendency in the corporate world is to learn (and adopt) a more open and transparent way of building a community around their products. Take for example the whole corporate blogging movement from Sun, Microsoft (and recently IBM). Or another example: the re-birth of newsgroups as an informal support method.
Also, in the open source community I can see a clear change in the way proprietary software is perceived these days. Today you don't really find too many people stating that proprietary software is downright evil, or the idea that it is an imoral thing to develop commercial software development. Instead, some of the open source proponents are starting to realize that the heated religious attitude that previously characterized the OSS movement is not a good thing. For example, Eric Raymond stated recently that the GPL might not be needed anymore!