I've been enjoying your commentary on various Twit network podcasts for a while now. On the recent MacBreak Weekly, I found your exchange with Merlin Mann about open source interesting. I detect a whiff of libertarianism in your remark about the force of the state being used to enforce taxes--which I appreciate, as I'm a libertarian myself. I'm also a patent attorney and have written extensively about why patent and copyright law are anti-free market and unlibertarian (my reasons may be found at The Case Against IP: A Concise Guide, available at http://www.stephankinsella.com/publications/#IP).
You are right, in a way, that the free market will come into play here--but the power of patent and copyright holders is not a free market power. It is an artificial and unjust monopoly given to them by the state, which they then use in the courts to get the force of the state (as with tax collection) to extort money from third parties. So, given this monopoly power, yes, the free market will temper somewhat how much they can extort from people, but still, it's unjust and greatly distorts the market. It also leads to hostility against the free market when people wrongly identify this state monopoly granting practice as part of the free market.
That said, I agree with you that there is no "religious" reason for a given individual or firm to use open source over non-open -- whatever works better and is the better deal for you, of course. And in fact the "open source" model is not without problems: it also relies on copyright, and has insidious aspects -- that's one reason I, as an anti-copyright type, prefer public domain or creative commons attribution only instead of the share-alike/GNU type model (which I explain in Copyright is very sticky!, Eben Moglen and Leftist Opposition to Intellectual Property, and Leftist Attacks on the Google Book Settlement).