Agreed. Anyhow, there is an open-source equivalent for any commercial software so talk of market saturation is nonsense. It is not the actual creation of the product that matters, it is the support for the software. That is where the divide between open source and commercial software lies.
However, if you are interested in the open source community then you are best getting involved in a current project. There are hundreds of projects that you could undertake like frameworks, e-commerce software, etc. You will get a better understanding of how the community operates.