Germany's experiment with a 4-day work week may not maintain productivity, but it could address wage inflation and promote more regular employment for part-time workers. Factors such as employee motivation, the digital economy, fertility, immigration, and the transition from manufacturing to a knowledge economy all impact labour productivity. Germany's productivity advantage is declining compared to Asian economies with surplus labour. Controls on movement of capital and labour are unsustainable, and economic growth relies on exporting capital and importing labour. Easier immigration and overseas investment can address labour shortages. Emerging economies are focusing on AI and energy transition to catch up, while larger investments in IT or alternative energy sources have transformative potential.