Thailand faces rapid aging population similar to Singapore, shifting healthcare focus from treating disease to preventing it and extending healthy lifespan. AI and data-driven personalized health monitoring—conceptualized as "Large Human Model"—can detect health risks before disease develops. Extending Thailand's healthy lifespan by just 1 year could generate ~$220 billion in economic value (half of GDP) with 16.1% ROI, making Healthspan Economy a business opportunity spanning self-care, preventive services, wellness, and AI-enabled hospitals.