I don't know much about the politics of the sport, nor have I been involved in any 4x, but having a goal to race nationally/internationally isn't the reason why a lot of people race. .
Some, and possibly a large fair majority do it just for fun. The social aspect, and fun factor being the biggest draw card. This is all at club level of course. I'm going to be getting into 4X and DS next year for the fun of it. I don't have the time (work), nor money (mortgage... LOL) or the skills/fitness for that matter to compete nationally. Through me wanting to get into it, I may possibly have brought with me two or three more riders to compete. It's nothing serious, but some good ol' fashioned competitive fun with some mates. That's the biggest draw card, not the possibility of competing nationally.
Like most things though, if the (rider) numbers aren't there, or the interest isn't there. The clubs won't push it or spend money to promote it (ie attract numbers), the lack of riders will also not help the larger, state and national events from attracting sponsors. No, or very few sponsors mean no money, no tracks, no equipment, no volunteers, etc.
In this scenario, the governing body should speak to local clubs, and the people/competitors in the sport. Ask their opinions and ask for their help to promote the sport. Then help said people, to raise the funds required for this through sponsors, fund raising etc. Then the flow on effect will be more events/facilities to attract members to the sport, make it family orientated, get the dad's racing, get the little tikes involved. Then when the youngsters see the club rounds and the entrants having a heap of competitive fun, they might want to get involved too. Getting the youngsters involved is where the national and international competitors will come from as they grow with the sport.
It's obviously easy to say this and that, implementing it is the hard bit, then pulling it off... Well that comes down to the people involved in the discipline now, to get involved, get out there and approach the clubs, approach the governing bodies to get organised and do something about it. Recruit more riders, sell the sport. Don't just type in here (not directing this at anyone, just generalising
). Get active and get involved.
Possibly, organisers should getting in contact/involved with other disciplines, BMX, DH, co-ordinating with these other disciplines to possibly run at the same event for promotional purposes (I understand this might clash as riders often do more than one discipline), but other people might not even know that a particular club or event does it. Bang, you've got a couple more people, they bring a couple of people, they bring a couple of people etc.