Windows 11 is currently undergoing a comprehensive interface overhaul and reorganization, and the issue of the coexistence of old and new interfaces within the system has once again captured the industry's attention. Microsoft provided insights into the reasons behind the prolonged presence of the old UI 23 years ago, and these considerations continue to shape the development of Windows 11 today, highlighting the real-world challenges encountered when innovating (or "revolutionizing") operating system interfaces.