The cost to transmit text is basically free and instantaneous. The rent (i.e. a GPU in a data center) vs buy is going to favor rent until buy is a trivial expense. Like 50-100 range.
Even then a LLM that just works is easier than dealing with your own
Video game streaming is the closest thing, and it's never really taken off. (And this, IMO, is a good comparison because it's a pretty similar magnitude up-front-cost, $500-$4000.)
Once the local-AI-is-good-enough (Sonnet level for a lot of basic tasks, say) for a $1k up-front investment the appeal of having something that can chew on various tasks 24/7 w/o rate limits, API token budget charge concerns, etc, is going to unlock a lot of new approaches to problems. Essentially more fully-baked line-of-business OpenClaw-type things. Or the smart home automation bot of Siri's dreams. You can more easily make that all private and secure when all the compute is local: don't give any outside network access. Push data into the sandbox periodically via boring old scripts-on-cronjobs, vs giving any sort of "agentic" harness external access. Have extremely limited data structures for getting output/instructions back out. I'd never want to pass info about my personal finances into a third party remote model; but I'd let a local one crunch numbers on it.
Even if you need Opus/Mythos/whatever level for certain tasks, if 95% of everything else you'd pay Anthropic or OpenAI for can now be done on things you own w/o third party risk... what does that do to the investment appeal of building better AI appliances to sell end users vs building better centralized models?
I think "what if today's LLM performance, but running entirely under your control and your own hardware" opens up a LOT of interesting functionality. Crowdsource the whole world's creativity to figure out what to do with it, vs waiting for product managers and engineers at 3 individual companies to release features.
Anyways, who's spending $1k for a LLM machine when they can spend $20 (or 0) on a subscription? And who's having an LLM crunching away 24/7 anyways? Anyone who is going to do something like that probably wants a cutting edge model.
It'll (probably) get to a point where the hardware is cheap enough and advancement levels off. But we're a ways from that and even then when a data center is 20ms away why not offload heavy compute that's mostly text in text out.