You are however entitled to represent yourself without passing the bar, and thus use the AI to help your case.
Even for the remaining lawyers, I imagine that their billable hours will crater due to competitive dynamics.
Billable hours will absolutely crater for lawyers who cater to a low-end clients (esp. for defense) and lawyers who are not good business people.
That said, the best lawyers will almost certainly still be in incredibly high demand, since higher-end lawyering (much like banking) is a personal business as much or more than it is a technical one. AI will simply allow these lawyers to do more and better work.
Surely unions are too powerful in several industries. Police, medicine, and law. But not having some association holding these people accountable is a bad idea.