I have shown how the internet has driven software prices into the dirt,...
For some types of software. As you also mention, vertical software markets are doing fine. Software is a means to an end, not a finite natural resource to be discovered or fought over between proprietary companies and open source, so I would assert that there are many ways in which to use software to increase the value of something, in a way that allows charging a higher price for it.
...created an environment conducive to open source collaboration,...
Hard to argue with that.
...and provided the infrastructure for that collaboration to actually take place.
Although you haven't proven that open source was necessary for that. It is certainly hard to imagine a flourishing community built upon proprietary email, IM, and forums.
I have also shown how cheap commodity software markets are necessary for open source development and how open source is not viable in less mature software markets without the necessary economy of scale.
Shown, yes, but not proven, and I doubt you can prove this given that open source development -- and even free software development, which is harder to initiate but self-sustaining -- predates commodity software markets.
When viewing open source development from this perspective, some things become clear that perhaps were not before.
The continuing expansion of the internet is necessary for continued open source proliferation.
Huh? The continuing existence of the Internet, certainly, but why is expansion required? The fresh supply of developers and users is inevitable unless all kids born after 2006 refuse to have anything to do with computers.
It does make one wonder, though: if you killed the Internet, could you kill open source?
...open source will continue to expand in scope, prevailing in more markets.
Agreed, and I think this is the only one you have proven with your economic argument.
There is no open source community.
I'm sure you can pick some strawman definition that you can refute, but there is indeed an open source community. A nontrivial segment of it is driven by idealism. A fairly large percentage of it even recognizes its membership in a community.
Your argument on this is bizarre: economic forces imply the creation of open source, therefore the open source community does not exist? Umm... perhaps the political environment within the United States implied the rise to power of someone resembling Ronald Reagan, but I'm pretty sure he still existed. Or, a more direct analogy: if you paid someone $10 if they would bring you back a flower, and as they were walking down the street to the flower store someone handed them a rose for free, then I think they would take the rose and thank the person, even though it may have appeared that the economic forces in the situation seemed to be implying that the flower store would sell one extra flower that day. So although economic forces may have made open source inevitable, that doesn't mean that the way in which it occurred wasn't controlled or at least heavily influenced by a small number of personalities and ideas.
Open source is neither good nor bad.
To me, advancement of human progress and improvement of the general welfare of the world is "good", and given that, I have to say that open source is a good thing. That does not imply that proprietary software is bad (and I'm not saying that it is or it isn't). It's a tossup. Proprietary software is available to benefit only a limited number of people, which is bad. The research and thinking that propagates from proprietary software to free software is indirectly good, as is the support for open source authors, etc.
Software patents, by this argument, are clearly bad. Their good stems from causing ideas to be generated and implemented that would otherwise languish. But their prevention of the utilization of advances for the good of humanity is bad, and unless you're a complete idiot you can see that the bad far, far overwhelms the good in the realm of software.
(Copyright is similar, but less bad and more good, so I can only speculate as to the final tally.)