[TFYS]

Depends on what the doctor can do with that inequality. If it means the doctor gets paid 20 times more than others then yes that is incompatible with democracy, as over time that wealth difference will be used to increase the inequality. But if the power is limited to only decisions about health, which is necessary for healthcare to function, then it should be acceptable. You'd still have to make sure that even that level of power is not used to gain more power, though.

[cjfd]

One can argue whether 20 times more is too much or too little but I would say that it is correct that a doctor gets paid quite a bit more than unskilled labor. Some people who become doctors might still go through with it if it were not but most (sane) people would not go through the lengthy and very demanding path that is medical school and residency if it was not a better paid than a job that very many people could do. I can tell you here and now that I don't think I personally would have had the stamina to become a medical doctor.

[TFYS]

Sure, I can agree with that. There does need to be some kind of incentive to do jobs that enough people don't naturally want to do. But the differences in rewards should be kept as small as possible and created only as a last resort. As I said, power concentration should only be allowed if absolutely necessary. If no one wants to become a doctor, then I'd consider it absolutely necessary to increase the incentives of doing so bit by bit until we have enough doctors while keeping in mind the risk that comes with the power differentials created. At some point an extra doctor might not be worth the extra risk of power concentration.