The idea is that 4-hours work weeks for relatively highly skilled knowledge workers will actually help lower the costs for the social security system (less burn

The idea is that 4-hours work weeks for relatively highly skilled knowledge workers will actually help lower the costs for the social security system (less burnouts, early retirements) and a more productive society (instead of 'grinding out' pointlessly long hours, work less and contribute to society in your free time) -- work is merely one way to be productive in society.