That makes no sense, though, and reeks of extrapolating a trend way beyond the conditions in which it is valid.

The simple truth is, cloud models are always going to be strictly superior to open ones, simply because cloud model vendors can run those same open models too. And they still retain economies of scale and efficiency that operating large data centers full of specialized hardware, so at the very least they can always offer open models at price per token that's much less than anyone else's electricity bill for compute. But on top of that, they still have researchers working on models and everything around them; they can afford to put top engineers on keeping their harness always ahead of whatever is currently most popular on Github, etc.