Where there are humans there is corruption, right? Not necessarily the internet, transparency and freedom of speech have slowly made the world less corrupt or at least made the corruption visible.
Open source is the combination of these three principles; internet, transparency and freedom of speech.
Proprietary systems are non trustworthy, you can't see what's going on behind the scenes. Open source systems on the other hand are transparent and allow for inspection and improvement. This is a very powerful principle and makes it hard for proprietary systems to compete.
Open source is a design philosophy which is not only applicable on software, the principle can also be applied on hardware and organizations. We now live in a world where it's normal that our hardware spies on us and organizations have their own secret agendas. To regain trust in those areas we need to apply the open source principle.