I think you're ignoring the inevitable march of progress. Phones will get big enough to hold it soon.

Instead of slapping on an extra battery pack, it will be an onboard llm model. Could have lifecycles just like phones.

Getting bigger (foldable) phones, without losing battery life, and running useable models in the same form-factor is a pretty big ask.

I think the future is the model becoming lighter not the hardware becoming heavier