I think you're underestimating the huge variety of productive apps in existence. For every system that handles >1M requests per second, there are probably at least 10 systems that won't even see 1M requests per hour. For example: Twice I've worked on apps for configuring motor control centers. I think you would consider these "productive" apps, but even if we had 100% market share there just aren't that many people in the world who need to configure a motor control center on any given day. The world is full of such apps.