Customers are a great way to finance a business for many reasons. First, customer financing is typically non dilutive. They want something from you other than equity in your business. Customers also help you fit your product to the market. And customers will help debug and improve the quality of the product.
We need new medical approaches to preventing and/or curing disease. We need new scientific approaches to generating, storing, and being more efficient with energy. Maybe we need more space exploration. Maybe we need more undersea exploration.
Investing in management means building communication systems, business processes, feedback, and routines that let you scale the business and team as efficiently as possible.