It'll be like software. The demand for both software and legal services is effectively infinite. If it becomes cheaper to file lawsuits then we'll get more lawsuits, not the same number of lawsuits at a lower price.
There will still be jobs for competent associate attorneys to prompt LLMs and review output. But frankly a lot of attorneys — especially many of those who attended "Third Tier Toilet" (TTT) law schools — were always a waste of money and should have never entered the profession in the first place.