I don't know how they are compensated, or whether they need to be, but IMHO no lawyer or judge should be allowed on the Supreme Court. The Constitution doesn't require it, and common sense would suggest that the final authority on the activity of the lawyerly fraternity, ought, in a democracy, be wielded by actual humans who live and work in the society, instead of those who hang around it and have been successful doing nothing more productive than leaching off of it.
If GWB were to nominate a non-lawyer to the Supreme Court, his popularity would go below 10 percent. The American people THINK that only lawyers can sit on the Supreme Court, and while they are wrong again as usual, they seem to relish in their collective ignorance.