Press enter or click to view image in full sizeFor decades, American ambition followed a well-worn script. The protagonists were bright, driven young people who understood that success meant climbing a particular ladder: elite college, prestigious entry-level job at Goldman Sachs or McKinsey, MBA from Wharton or Stanford, then a steady ascent through the corporate ranks toward the corner office. This was the royal road to joining what sociologists call the professional-managerial class: The stra...