Where cost is concerned, I think of the action shooting sports as being in the same level to somewhat more expensive than BR.
I know several people that shoot it, with nice equipment on a fairly limited budget. The biggest difference in cost IMO is practice time, ammo cost(volume) and associated upkeep. Some shooters spend considerably more than others in this respect. I know a very good shooter, who is no world beater though, that shoots an average of 600 rounds per week, practice. Most don't put in this much effort. But it averages out pretty close to BR costs across the board.
What I think we have to recognize, is that action shooting is growing despite the costs, has a much larger base, and that it has a lower median age for participants. The age issue may or may not be offset somewhat by the more physical nature of the game driving some of them out earlier than in BR.
So why??
What I see is better marketing, for one thing, through TV, magazines and internet.
Another,is accessibility to ranges holding these matches...often only a few minutes, not hours or days from home.
Maybe most importantly, they have classes in which they can shoot their "justifiable" and /or already owned guns. i.e., handgun(personal protection), AR15(PP, hunting,plinking), and shotgun(PP, hunting, or other). So, they can go compete in a lower class with unmodified guns they either already own or simply aren't as specialized as a BR rifle is. Face it, these rifles aren't good for much else, except maybe as a prarie dog gun in some cases
. This is IMO the biggest difference in getting new participants to give it a try. They don't have to go spend 5-10K on highly specialized equipment to find out if they like it or not, or to compete in general in the lower divisions. They have a list of factory guns that are legal.
Perhaps this is what factory class in BR should become....i.e. Unmodified Savage only or the like. That would make policing factory class simpler.
They also have divisions for different levels of shooter abilities and well defined(albeit complicated at times) rules.
I'm not advocating anything here, just pointing out some of the differences that I see and that I don't think it's as simple as cost alone.--Mike