I'm not sure if I can speak for everyone else. I transferred from the primary reserve to the regular force because I couldn't get a job after graduating from university. I was the seventh in my class of 35 electrical engineers to get a job by joining the regular force. One of my classmates ended up joining later on because he couldn't get a job.
Initially, I think you look at where the person's from. A lot of times it's financial. There might be no financial opportunities where they are. The armed forces is a stepping stone to a better life. For instance, when I joined the regular force, I didn't know if I was going to like it. I set up a plan so that if I didn't like it, I could return to the reserves. But I loved it. I've been in it now for 38 years, so that tells you right there.
It's like anything else; you don't know what you're really getting into, at first. Some people try it. If it works out for them, if they enjoy it and they're challenged, then they'll stay, but if it's just a mundane job where they're pushing a broom around an armoury day after day after day, you'll lose them.