There are plenty of cases to be heard without frvilous ones.. and contrinbuting to legal aid just means more people get to bring more expensive cases... Anyway, judges are salaried, so they get the same whether they are in court or not..
They usually make their money while they are barristers.
When I lived in San Francisco, I teased a lawyer who was doing her California bar exam, citing she wanted to become a judge... My response was, "with the money attorneys make, what... are you not a good lawyer?"
I wasn't prepared for the tirade that came...