> I suspect the economics favor centralized servers, if you only look at the aggregated cost to serve X number of users' tokens.

The economics of real-time, low-latency inference of very large near-SOTA models will heavily favor a centralized setup. But if you can afford to wait for your answer - be it a day, a week, or even more at the extreme low end (or if you just stick to leaner models for your relatively quick replies) the economics start to shift in a very clear way. A slow-going local inference setup relying on cheap SSD offload does not need the high power input of a datacenter rack, and the cooling load is outright trivial - even when working on many requests in parallel, which (in a SSD offload context) is what maximizes throughput even for local inference. These are serious problems for centralized inference that will probably limit the scale at which it can be applied.