From your source, a NPV of ~$680k in accumulated earnings over 30 years is the average return. That is ~$22,600 earnings per year. I don't think that is a good

From your source, a NPV of ~$680k in accumulated earnings over 30 years is the average return. That is ~$22,600 earnings per year. I don't think that is a good return by any means. Am I reading the chart correctly? If so, I don't see how your link favors your argument.