My personal idea revolves around "can I run it on a basic smartphone, with whatever the 'floor' for basic smartphones under lets say $300 is for memory (let's pretend RAM prices are normal).

Edit: The fact this runs on a Smartphone means it is highly relevant. My only thing is, how do we give such a model an "unlimited" context window, so it can digest as much as it needs. I know some models know multiple languages, I wouldnt be surprised if sticking to only English would reduce the model size / need for more hardware and make it even smaller / tighter.