Modernize now or risk losing decades of competitive advantage as mainframe developers retire. CEOs, CIOs, and Technical Directors face a critical strategic window as the modernization market grows from $8.39 billion in 2025 to $13.34 billion by 2030. This executive guide evaluates major platforms including AWS BluAge, IBM Watson Code Assistant, Microsoft Azure with Raincode, and specialized vendors. Leadership teams must address the institutional knowledge crisis and manage organizational change beyond selecting technology. Discover how to evaluate vendors, preserve critical business logic, and build modernization strategies that secure your organization's digital future.