How much do you really make selling solar?

I'm curious, how much can one really make by selling solar energy systems? I understand it's a growing industry with many benefits for both the environment and consumers' wallets, but what kind of profits can be expected? Is it a lucrative business venture, or more of a long-term investment with moderate returns? I'm interested in hearing your thoughts on the financial aspects of selling solar, and what factors influence the potential earnings in this field.