I think it’s moreso that the more developed any one project is, the fewer low hanging fruits there are to pick, so there’s less beginner tasks to do. That being said, there are still new projects springing up every day, but we just don’t know which of them will be the next Linux or Python.
The exact words I had in mind: 'the low-hanging fruits'. But you expressed it more accurately than I was going to. All the simple stuff has been done.