There are two reasons that doesn't matter. The first is that it's untrue more often than not; plenty of people could do both. And the second is that "doctors and lawyers" are just arbitrary stand ins for high paying domestic jobs. They could also become physicists, commercial airline pilots, Wall St. quants, actuaries, etc.
>plenty of people could do both
Citation heavily needed.
Because here in the real world the barrier to entry in SW engineering jobs is significantly lower than the law bar or med school. Not to mention cheaper.
And yes of course, Americans have the highest salaries in the world for white collar professions, what other new information do you have that we don't already know?