In addition, programmers have many more domains that they can switch into, however, once the AI lawyer or AI doctor will rise, it would practically replace 90% of the lawyers/doctors.
Note that the earning are protected mainly because you invested the time , and not because of some union.
The Achilles heel of those professions, is that the body of knowledge is constant, with very long half life. But this also make it ready for automation.
With AI, the destruction of those professions will be quick, as they will get destroy from the bottom. I.e. Even if AI make existing lawyers twice as productive, it would mean that you would need half the lawyers. If AI will make them 4x productive, you would need 25% of lawyers, etc.
Most visits to doctors it is not about only about the sickness (or information about what medicine to get), but about socializing and somebody inspect you and discuss with you. This part, the machine cannot do. It is what is called the doctor-patient relationship. If you think this is not the important part, I cannot disagree more with you.
I go to doctors only when I really need, but the pattern I see around is that people have a real long lasting trust relationship with the doctors they see.