The educational requirements for engineers to enter that profession is nowhere near that of doctors and even lawyers. An engineer can begin working after four years of college; lawyers seven and doctors eight plus various lengths of time in residency.
Those aren't really comparable.
My undergrad degree is in Electrical Engineering (1968) and after a few years working as an EE, I went back to school and became a lawyer, JD in 1976.
Engineering undergrad degrees at the time required about 20% more credit hours than for other majors, so it was really a five year program crammed into four years.
I personally found law school easier than master's level EE classes.
I took a 25% pay cut, by the way, between my last paycheck as an EE and my first one as a newly minted lawyer. However, after a few years of hard work, my income as a telecommunications lawyer was substantially more than it would have been had I remained in engineering.
Jack