Compute has gone back and forth from mainframe/thin client to fat client a few times already. LLMs will probably follow at some point but I think it's going to take a long time.
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
Except that buy is a trivial expense because the hardware has been bought already. You've got a whole lot of iGPU and dGPU silicon that's currently sitting idle as part of consumer devices and could be working on local AI inference under the end user's control.
Storage has moved back and forth but I don't thnk compute has ever really gone back to thin client. Even Gmail, Google Docs, etc are running a buttload of javascript on the user device. Various attempts at avoiding that (remote .NET or JVM stuff on early "smart-ish" phones) crashed and burned.
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.