The problem with medicine is long long years of training which involves some of the best years of your life. Many doctors have not learned how to live. Many hobbies and joys in life are shaped during your teenager years and 20s. Most doctors are studying in these years. As a result, when you are 40 and you make a good money, you don't know how to live and how to enjoy the money.
The other problem with medicine is the end result of what you do. If you see it as an outsider, the end result is not really rewarding.It is not like building a new house and enjoying your production. In most cases, you just prolong the disease or marginally improve the outcome. Still the end point is not promising.
Medicine, due to its long years of training, is like joining Mafia group. Once you join it, there is no way out. After finishing a residency, there is not a lot of ways to get out. Even you are not able to switch fields easily within medicine. This is not the case in most other fields.
I agree that the grass is always greener on the other side. But Medicine is a life long commitment. It has a huge influence on the rest of your life. Let's be honest. Outside medicine, our skills are very limited. Even within medicine, your skills are limited to a very narrow field. A CT surgeon can not work as a family doctor.
Though money is not everything, but it is an important factor. The previous generation of doctors had much less years of training. Medicine was less sub-specialized. The hours were much better in 80s and 90s. And the pay was (much) better at least per case across all fields. Society was more respectful towards doctors. Nevertheless, retired physicians from the previous generation are not sure whether they made a right choice at that time. Now these days with more work, more hours, less pay and more training, I really doubt that for a 20 year old medicine is a good choice.