It's not possible for models to replicate across consumer computers (without a major advance in distributed computing, at least), but that doesn't mean they can't replicate at all. There are services that'll rent you GPU pods by the hour with zero oversight, so even today, if a model can get access to some money and exfiltrate its weights, it can rent a bunch of GPU pods and run itself there.

(It's not going to be trivial, because it's possible the model was meant to be ran in a proprietary way with a custom framework and a bunch of optimized kernels and such, but I think transforming it to be ran in just vllm is the "a few days of work for a human" sort of task, and hence not a big deal for an LLM smart enough to exfiltrate itself in the first place.)