It would be so simple if we did, I go for a year out from my current branch letting someone else into my slot. I go to a remote new branch and help train them up, get an excellent report and then return with a promotion. (Also proving I've got over a number of personnal problems during this period). Suppose this is like problems Bde Training Teams face on returning to their unit. If it was a civvie company it'd be a very good plan, I can be replaced in my current region easily and I'd bring a lot of experience to a branch in another region, but with the TA my hard work would be ignored outside the new branch/region and returning to my current branch/region means I re-start at the bottom of the pile (with any previous baggage intact). Suppose put another way, a CSM/SSM or SQMS/CQMS (and others) can do their job very well regardless of their cap badge. So why should WO2 Bloggs have to move to a unit 100 miles away, when another corps in the same TAC and/or city has a vacancy (in another corps/regt) and they are best for the job?