Serious comment: how does comparing productivity (or anything) by dividing into GDP work - let alone to three significant figures - when all countries measure GDP differently?
The USA for example includes about $7t of hedonic and imputed values that a) never happened in the real world, but b) exceed Japan's entire GDP.
US: Large public sector of debatable value (please no flames)
Japan: Paves entirety of Yokohama
China: Tofu real estate and more...
I agree that it is silly. If the state or the public sector digs holes and refills them, it adds to GDP. Typically economists say, "Yes, GDP is a flawed metric, but it is better than no metric"
That said, we can evaluate the added benefits of automation and the productivity gains thereof, purely from first principles, without resorting to empiricism.
The USA for example includes about $7t of hedonic and imputed values that a) never happened in the real world, but b) exceed Japan's entire GDP.