Aspiring managers absolutely should be attending meetings, volunteer efforts, etc. on their own time to develop leadership skills.
Surgeons and police officers are well-trained, but it is not usually considered creative work. On the job training is designed into the curriculum. In some cases, a surgeon may be innovative and develop new surgical techniques. In those cases, yes, they are basically operating on their own time. It is either pro-bono work or a teaching hospital, and the patient is willing to take a chance on a non-standard treatment.
Programming is creative work. Every problem is a new experience requiring a unique solution by a combination of past experience and knowledge, while incorporating fundamentals of science and math. Building this base is not necessarily well covered in school. Unfortunately, many curricula are eliminating internships and apprenticeships.