There are too many variables. Autoregressive LLM architectures are not diffusion architectures are not JEPA architectures. We can't say right now how architectures are going to evolve or which one will become prominent even in the near future. There is still so much efficiency left on the table.

Plotting cost against power usage and elapsed time will tell you very little other than what the lay of the land is today. If you are truly concerned about the long term effects, then you need to account for long term evolution.