But there are also a lot of companies set up by good people who care deeply about their subject and who wish to try to earn a living doing something they love. 18 years ago people where probably saying "That young Ray Mears fella whose he then? - he'll never make it no experience."
This is a good point Gary.
There are a number of dedicated people who start-up part-time 'schools' because they love the subject and feel they have something to offer but also feel they are not in a position to launch into a full-time venture.
For my part, I enjoy running occasional workshops and demonstrations alongside my main job. They key with this is to recognise the limits of one's expertise and only teach those subject where you feel appropriately accomplished. My approach, given the limited time I have each year, is to concentrate on teaching the basics to give people with little experience of the subject a solid foundation and real enthusiam. I stick to a tried and tested course programme where the emphasis is on helping people to fully understand the core skills through clear, structured learning. If people want to go on to learn more specialised or advanced skills, I can then point them in the right direction, be it with me or someone else. What a
good instructor would never do is take money for teaching beyond his ability just because he's 'hooked' a loyal student. All teachers have a responsibility to be honest and to steer a dedicated student in the most appropriate direction even if that's away from their own schools.
The other point about part-time instruction has already been made. A lot depends on what the instructor does at other times. I agree that many jobs do not allow a person to always maintain their skill and experience. However, sometimes having another job can enhance the experience an instructor can bring to his/her students. I am fortunate to work in wildlife conservation and ecology where I get to use 'bushcraft' skills such as animal track & sign identification and plant identification in a professional capacity. Prior to this, I also spent many years teaching outdoor environmental field-work and some outdoor pursuits to people from all ages and backgrounds, in all weathers. I also voulunteer for my local Search & Rescue team. All of these 'applied' aspects provide useful experience just as Gary's army career has, but don't always come with the label of 'Bushcraft'
The point is that although a school may be part-time, its instructors might actually be practicing elements of bushcraft, nature awareness and teaching (in less obvious ways) 'full-time'. Conversely, many full-time schools employ good part-time instructors to lead some of their courses. Any 'rule of thumb' on course selection should bear all this in mind.