If proverbial Martians descended on Earth and toured America’s crowded shopping malls, traveled its congested highways and sampled its technological marvels — from the many cable channels to ubiquitous smartphones — these visitors would be hard-pressed to describe the United States as poor or its economy as failing. The truth is that, even in its current unsatisfactory condition, America is an immensely wealthy society. It produces $16 trillion in annual goods and services, provides 136 million jobs and supports a median household income of $50,000.