They made a claim about language models in general, not just ones that had been released so far.

The point of the paper, in fact, is that language models are getting "too big", and another approach is needed to make progress, so they were certainly predicting things about later models.

With that said, they talked about "pure" language models, so it is fair to say that they didn't talk about, say, LLMs that are multimodal or that have tool use, which are advances that happened after their paper.

They did use RLHF at the time, at which point it is not a pure probabilistic representation of the training corpora. Bizarrely, RLHF never came up in the paper.