> You might argue that productivity gains will stop at some point, but then you need to provide arguments for that, not take as a given that there is a limit.

I have one. Productivity gains are mostly granted by energy (AKA bigger machines). W/capita is imo a better approximation to a nation wealth than GPD/capita in socialist countries, but even in the us you can see the strong correlation.

80% of this energy come from fossil fuel, coal and gaz make 60% of world electricity (probably more), and oil for movement. This is the limit to growth.