If you look at all examples in this thread all the software they refer to is GUI based non-technical applications. I think this highlights where Open Source co

If you look at all examples in this thread all the software they refer to is GUI based non-technical applications. I think this highlights where Open Source competes the most, applications which the engineers build for themselves. Apache, for example, makes building a paid for web server pretty uneconomic (IIS is bundled). When engineers doing Open Source are scratching their itch they tend to make world beating products, when they aren't scratching their own itch the momentum tails off because there isn't another driver (such as a wage, or a product manager).