So by your logic we need more pool cleaners in the industry?

When you build an app you consult with the people that need it. As I said, pretty clearly, my example was as on-the-nose as I could possibly make it to give you a jumping off point for understanding more subtle ways in which adding diverse perspectives helps identify and solve new problems.

I don't have enough experience with software project management to explain it back to someone who thinks that different problem solving strategies don't apply to engineering. Problem solving is the core of engineering, no matter what kind. I can't answer your question. You are asking me to dream up an application, and then identify a problem that someone who is not me would identify that I would not have identified, you might understand why this would be difficult.