I think this pipeline already exists via open source software. Unskilled people are by default allowed to try contributing. As soon as they are actually capable of doing so, they can move up the ranks by getting hired somewhere.
However, I'd argue that unpaid contribution to open source software as a way to build reputation is not absurd, because the value you are creating is still available for you to use and benefit from. Additionally, you are free to work on anything you like - something you can't do at an organization which is compelling you to work for free.