A doctor's starting pay (family practice) is $175,000, with maybe a $100,000 sign on bonus. More, if you practice in a remote area where no one wants to work....
A PHD engineer will be lucky to start making $175,000 10 years later.
Both spend about the same amount of time in education.
Not everyone is cut to be an MD.
Given the huge pile of student loan debt and 60-80 hr work weeks for typical MDs, I'll take being an engineer any day. Got a PhD engineering in 4.5 years after BS, zero student loans, >$175k after 4 years at Intel (grade 8 in OR), and maintaining a 40-45 hr workweek. MDs also have 3 years of residency and more of fellowship after school, with 80hr wws and low pay.