This seems to be ignoring the major force driving AI right now - hardware improvements. We've barely seen a new hardware generation since ChatGPT was released to the market, we'd certainly expect it to plateau fairly quickly on fixed hardware. My personal experience of AI models is going to be a series of step changes every time the VRAM on my graphics card doubles. Big companies are probably going to see something similar each time a new more powerful product hits the data centre. The algorithms here aren't all that impressive compared to the creeping FLOPS/$ metric.

Bear cases always welcome. This wouldn't be the first time in computing history that progress just falls off the exponential curve suddenly. Although I would bet money on there being a few years left and AGI is achieved.