This is great advice for life in general, esp for younger folks starting a career: in whatever industry you're in, the active doing-of-things and taking responsibility for them, whether they are 'officially' yours to be responsible for, will begin to lift you, little by little, in a compounding fashion. You became, over time, somebody whose opinion people value.
Very well said. This aligns with my own experience. Open source, like other volunteer projects, generally allows new people to insert themselves and participate in some niche and often overlooked aspect. If that participation creates value, your influence grows. If you stick with it long enough, you essentially become the hub of that sphere of influence that you have built. These hubs do not usurp the work of others, but rather enhances the overall project and over time you become the trusted and indispensable go-to person for that area. It's a very empowering feeling and one that carries over to other aspects of life.