On Edit: after reading the post that went in while I was writing mine.. I'm with you on 9 pin, I've said this before, I have had massive amounts of fun bowling kegel 9 pin in Coffs before, and I have gotten a strike in it too, was really exciting too!
Here's an interesting thought about ball restrictions...
(I want to preface this by saying that I realise the Golf analogy has been done to death, but here I go..)
In Golf you are allowed a maximum of 14 Clubs. 14. take that in for a minute, golfers carry 14 different pieces of kit to help them improve their score. Do they NEED 14 clubs? no way, if you good enough, you can hit a driver 50 meters if you need to... the difference between an 8 iron and 7 iron is marginal at best (I do play golf by the way, not great, but not terrible either, just wanted to point that out), but they have these different clubs in their bag to make the sport what? more difficult? no... EASIER.. funny thing is though, no one even thinks about that...
We have multiple balls to cover a variety of different "landscapes" we may encounter when shoeing up to bowl. Just because we can't actually see this landscape doesn't make it any less relevant, if anything it makes it that much more difficult.
Bowling is definitely in decline, as with a lot of other sports, it's just that way it goes, trends shift, popularity of certain things have ebbs and flows, for all we know bowling could make a comeback in the next 5 years, I don't think it's likely, but you never know.
The one thing I do know is that back tracking is absolutely not the right answer, in fact it would more than likely kill the sport faster, as the equipment manufacturers would go broke, and the support they give would disappear, and that would be all she wrote.
Honestly, I doubt that there is much we (or anybody) can do about it, I know that sounds apathetic, it's not though, yeah, we can make league bowling harder, sure (I'm in the pro camp on this, I find I score better on harder patterns) we could limit the number of balls allowed in your bag at any one time (could be interesting for certain events, but not across the board, and if so, make it 14, he he). There will be people who run from the sport if changes are made in any direction, but a move to make it more difficult will more than likely drive people away, especially at league level.
Having integrity is great, it really is, but having integrity in a sport that is dead, really doesn't mean much...
I do like the idea of having levels of competition, and placing the correct level of "Importance" on each level, This has been brought up before (I think it was Belmo and Michael Little many moons ago) which rang true to me, each "level" of competition would have different criteria for that level, and the higher the level, the more recognition you receive for achieving certain things (honor scores, etc..)
Something needs to be done, but what and how, is all guess work at this point, no one knows what would work, and the only way to know would be to try it, the risk is, if you try the wrong thing, and the sport down further down the drain, rescue could be impossible, hence why the bowling world is hesitating to make a move...
Of course, all of that is just my opinion...