I don't think the boundary between "generalization" and "metaphor" is very well defined. When you go from an exemplar of 1 to 2, you're going to find all kinds of edge cases where attributes of the thing being demonstrated that had seemed to be essential turn out to not be necessary.

I think you certainly could look at LLMs as "thinking" metaphorically, but I also don't think it is necessarily only a metaphor.

Well, it's unusual to "generalize" an idea if you only had two exemplars, one so old and so complicated that all your terms are specifically referent to it and often even hard to be precise about; and the other is both extremely novel and plainly distinct in both its mechanisms and behaviors.

While maybe that boundary can be fuzzy, we're unequivocally and deeply in "metaphor" territory here.