Simple economics are not the best representation of reality.
For many pride in one's work can matter more than pay, the engineering profession attracts some of the most passionate do-gooders (Gates to name a famous example) who care about the world improving. They aren't usually recognized for it because they try to improve the world by fixing the systems rather than flying to a 3rd world country and building a house.
Additionally, in reality but not in simple economics, there is a huge gap in value-generated for the company and perceived-value-generated for the company. In fact, there can be situations where the two are negatively correlated and the engineer knows best.
Finally let's remember that short-term value to the company isn't the end-all-be-all. Did you know Zynga had some individual users who spent over 100 grand on virtual items? Great companies often arise by ignoring the short-term-profit and focusing on delivering a great product with a great experience, even if the market for it doesn't exist yet (i.e. what google did)