Anyone called a doctor requires a ton of schooling/practice. To get a doctorate of philosophy, there's the bachelors, the masters, the doctorate, the practicum year, that's 12 years, and the person isn't even licensed at this point.
Medical Doctors also spend about 12 years, same with vets, or oral surgeons, or whatever...
Lawyers only spend about 7 or 8 in comparison. Scientists it depends, if they have a doctorate then absolutely.
Astronauts go through rigorous training as compared to just years of education (not sure if you're adding the training as part of it).
Politicians don't usually have higher level degrees (i.e. doctorates), it is much more useful for a politician to have experience than it is for them to have an education.