Okavango,
You are quite right, however many currently embarking on flying training and parting with £100k+ believe that the reward for that kind of investment should be the pointy end of a shiny jet and not poling around in a piston a/craft that is older than they are.
The problem with many of the options that you mention is that, other than instructing, they require some level of experience/hours beyond a basic f/ATPL & 200hrs.