Or to put it another way, to artificially erect barriers to entry that ensure they get paid more than they would in a freer market.
Now imagine that guy representing you at a murder trial.
I like the barriers.
It's also worth remembering that plenty of indigent people in this country are effectively represented by 'that guy,' including in murder trials. Look at the cases of Calvin Burdine or George McFarland, both of whose court-appointed attorneys slept through their trials. Are those barriers really doing what you want them to do?
The top computer programmers also make as much as top lawyers and doctors - possibly more if you count entrepreneurs.
It's not so much a price / cost issue as it is a respect issue. Can you imagine how the legal or medical profession would suffer if anyone off the street could claim to be a lawyer or doctor and get hired for the job?