Commercial impact wouldn't apply to the model, it would apply to the use of the model.
In Betamax, SCOTUS held that a tool doesn't infringe provided it can "sustain a substantial non-infringing use." There is no question that an LLM can sustain a substantial noninfringing use, e.g., analyzing police reports for New Orleans Innocence Project.
A user of an LLM might infringe copyright, but the LLM itself doesn't.