Increasing the availability of useful tools to anyone interested in software development and computing / technology in general is where I think FOSS has excelled.
A simple example might be a free, open-source blueprint for a typewriter. People can improve the blueprint, anyone can use it. Now, to build an actual typewriter based on this blueprint, there's where individual investment of time and money is required - but anyone can do it, there's no patent lawyer waiting to halt that process.
Note also that branding and reliability do matter even in open-source. Two typewriter manufacturers working off the same open-source blueprint could make very different quality typewriters, and the one with the better reputation has a market edge (just not one based on exclusive access to some old IP).
Now, let's say you use the typewriter to create a best-selling novel. Here the creator should be able to retain rights to the novel, and since good writers are not all that common, the notion that the novel should be free and open-source doesn't really work that well if we want to have writers making a living and continuing to write. An alternative approach, such as a state-sponsored program to support authors, or a billionaire-financed private foundation program, would quickly become little more than a propaganda factory.
The kind of scenario that gave rise to the open-source movement might be described as the notion that authors who used a propriety typewriter to write their novel owe a fraction of their revenue to the typewriter blueprint owner. The whole Oracle-Google-Java-Android business comes to mind for example.