What would you advise others who were planning to enter that field ?
No matter the field... no matter the good and the bad....
Assuming that the person is entering a field as a young person, chances are what's right for today will be wrong for tomorrow.
When I started with Sears, there were 7 " executives" in every small store. That pay in 1958 would be about $70K today. The salesman in the suit department retired with $300K in profit sharing which would be $2.14Million in today's dollars.
Today, there would be only one manager with an average pay about $58K, and of course, there are few salesmen in most stores, and no profit sharing.
My suggestion for choosing a profession would be to get a crystal ball or hunt the internet for the smartest most future looking wise men.
From just a very few years ago, consider the change in job opportunities for mathematicians, geologists, lawyers. The neartime future looks to be in Healthcare, IT, Alternate energy, with emphasis not only on specialties, but increasingly on teaching within those specialties. The sleeping tiger may well be in globalization... with emphasis on languages, cultures and the financial and management styles that will be necessary. Intenational law will be very popular. This once again puts a premium on liberal arts schools.
Most assuredly, though, whatever seems right today, will be passe in 20 to 30 years, so whatever we think we've learned and whatever that 20 year old who is choosing a life's career today... probably won't be much in demand at the time of retirememt.