From my limited understanding of this AI field, that it cost over million $ to train the model, after that the the query against the model is fast and doesn't cost a lot money. So with this AI/LLM it is more about the upfront cost, and how well the model is train using that millions dollars, and according to some data expert seems to be an art and a science [1]. Some AI experts here please correct me if I'm wrong.

1: https://www.amorphousdata.com/blog/time-series-vs-regression