A couple of things I find interesting.
Firstly, it sounds to me like there's a very good chance in the military that you WON'T have a 10,000+ or even a 5,000+ hour instructor teaching you, for better or for worse. More like 1,000 hours, maybe 2 or 3? Any pilot with 3, 5, 10 or 20,000 hours knows how LITTLE they knew at 1,000 hours, regardless of what kind of flying they have done. I just think that's an interesting statistic. If you seek EXPERIENCE from an instructor, ie time in the saddle, there is a good chance you will get more from a civvie instructor then?
Secondly, maybe this hour building by instructing is big in the US or UK, but I don't think its such a big thing in Australia, from what I've seen. You can't finish your CPL in Oz and walk into a rotary instructor rating, you've got to have 400 hours minimum. Most pilots that get to 400 hours are already in jobs and so are getting hours anyway.
I know that when I did my instructor rating my motivation had nothing to do with building hours. It was simply this: I wanted to feel that if ever I was flogging along in a single and the engine stopped or I had a TR failure or some other emergency, that I'd feel rehearsed and confident in being able to put it down in one piece.
I have no doubt that instructing was good for that, you do hundreds if not thousands of autos and emergencies over and over again. In a year of instructing you'd probably do 10 years worth of emergencies that the average line pilot does on check rides.