Reddit isn’t profitable, despite having more than 50 million daily active users. In preparation for an IPO, CEO Steve Huffman put the platform’s API
Linux Kernel is kind of a bad example since its one of the examples of project scaling with many people from many companies. Even if you want to go with its inception, it came from Unix which already had many people. Of course, its also one of the best examples of actual leadership, proper technical people management, which is something very hard to come by. Its also a great example of how to divide your design and make it scalable, so people are working on different parts totally independent on each other.
That’s all actual, proper, work, not whatever crappy slide presentation passes as leadership on many places.