There is an implicit assumption here that models are being 'trained', perhaps because LLMs are a hot topic. By models we are usually talking about things like decision trees or regression models or Markov models that put in risk probabilities of various eventualities based on patient characteristics.

[Citation needed]

If these things were being based on traditional AI techniques instead of neural network techniques, why are they getting implemented now (when, as you say, LLMs are the hot topic) instead of a decade or so ago when that other stuff was in vogue?

I think the assumption that they're using training data is a very good one in the absence of evidence to the contrary.