I don't think that you can characterize or generalize amateurs, professionals, or teachers for that matter.
Pros do it for money. Amateurs do it for fun. There is a great range in teachers. Some are simply poor business types who can do good photography but can't handle marketing or other aspects of running a business. Some simply have no idea how to start a photography business.
In some colleges, high schools, and even arts schools, less than talented administrators may assign almost anyone available to teach photography in a particular time slot.
As to pros, there is quite a range from those who deal with the general public and may not require a high degree of either skill or talent through to those whose position or work is dependent upon maintaining extremely high standards. There are the specialists who only do sports, portraits, models, fashion, weddings, events, etc. through to generalists working for a large organization that may be doing public relations and photojournalism one day, and sports, fashion or business portraits the next. All pros are not necessarily great photographers but most do retain their artistic flair, if they had any in the first place.
There is quite a range of amateurs as well. At the low end are those who think they can simply point and shoot and create terrific artistic photos without any knowledge, learning, effort, experience, or practice. At the top end are those with background and experience equal to that of most pros with the only difference being that they have seldom if ever been paid for their work. Some amateurs without an artistic bone in their body, think that they are artistic photographers and a few actually have considerable talent.
skieur