"I work on a software product in a niche, within a niche, within a niche, to help a subset of large corporations process data a little bit more effectively during meetings."

Even a small increase in efficiency in a large company can be worth a lot of money, and that money will be spread across employees, customers, and shareholders. So your work benefits people, even if it does so indirectly. In a simple economy where everyone is a farmer or produces goods for farmers, it's easy to understand what people are contributing. In an advanced economy this is more difficult to understand, but the specialization of an advanced economy creates much higher living standards.