Most measures of AI progress closely fit an exponential over the 2023-2026 period. Meanwhile AI capex over the same period has been slightly super-exponential (i.e. the rate of growth itself is increasing).

So if you model AI as a system that takes as input external investment and outputs AI progress, that system has a slightly sub-linear response.

But super-exponential injection of *external* resources is not sustainable in the long-term. To achieve sustained exponential progress, the AI industry will need to achieve matching exponential profits -- it will need to close the resource loop.