>Whether these training set predictive patterns result in the model performing as you might hope on an unseen text depends on the similarity of that text to samples in the training set.
yes, except the computer can easily 'see' in more than 3 dimensions with more capability to spot similarities, and can follow lines of prediction (similar to chess) far more than any group of humans can.
that super-human ability to spot similarities and walk latent spaces 'randomly' -yet uncannily - has given rise to emergent phenomena that has mimicked proto-intelligence.
we have no idea what the ideas these tokens have embedded at different layers, and what capabilities can emerge now or at deployment time later, or given a certain prompt.