Dare Obansanjo: "A key benefit of Open Source/Free Software to software consumers is that it tends to drive the price of the software to zero. "
Another conclusion is that the 'software business' is breathtakingly inefficient and what we mean by "zero" is relative. In that light, a key benefit of Open Source/Free Software is that it reduces waste, via a sort of proto-industrialisation. The cost benefits of not writing software get passed back to consumers, not unlike the way Gutenburg, Wedgwood, Colt let more people have better books, crockery and guns at lower prices, and then McLean helped distribute them for zero, which meant they could be made anywhere.
Even OSS is in need of some rationalisation. Individually it's fun to keep rewriting web frameworks, content management systems, enterprise middleware, build systems, interface definition languages, AtomPub servers, and so on. At a macro-economic level it's a waste of electricity and natural resources - that might come to be seen as unethical (I know, that's crazy talk :). IOW maybe it's no harm for green computing efforts to be looking at waste in software itself, and not just physical things like computers and datacenters.