The only metric that really matters is 'profit per amount invested'. This is very difficult to quickly evaluate, and therefore we resolve to use simplified metrics such as cost per unit tokens.

The point at which the metrics become meaningless is when others become aware of them, and begin to optimise for them. Lines per code is is not a bad insight for development activity, only when the developers are not aware of the metric. Price per 1M tokens became meaningless when LLM providers started to optimise for it. It seems to be that Sonnet 5 is optimised to score well on AA intelligence whilst seemingly having a lower price per 1M tokens.

I think generally we are in an AI bubble, and it will at some point pop. The numbers simply don't make sense. I would gamble heavily on local cost per task to survive the LLM winter. Given that hardware is pretty much a fixed overhead, you probably want to optimise for task per kW - that's where I'm betting.