The path to becoming a medical doctor is quite long in the U.S. I don't think I could handle the stress of it all. People often cite helping others and making money as the main advantages of being a medical doctor, but I think other paths can do both better. The high pay cited only comes after many more years of training for specialization and highly competitive residency. Such time invested in other areas (MBA, etc.) would yield good income. People who are, for instance, bioengineers, can potentially help millions of people with their work whereas a medical doctor typically helps only the patients they see in their lifetime. Perhaps they meant the personal instance of helping people?
There are people who do not waver from the intent of becoming a medical doctor from a young age, and go on to achieve their goals. I lack such motivation.