I know X will find this offensive but ^^
Sorry mate!
It's all theoretical! No-one knows what would happen if RA became bankrupt and folded - I suspect they'd apply for government money to keep them going - but I can say with a high degree of confidence that whatever happened would end up in some court or other. Lawyers are doing well out of Rugby Australia over the past few years!
If RA folded, NSWRU would simply step in, claim primacy, say it is a short term temporary measure only, cancel the NRC, punt the Brumbies and Rebels, choose the Wallabies side, and then decide how the money from the Wallabies side got spent (because that is exactly what the Wallabies are, a side picked by and for RA as the body that represents Australia). So essentially, Rugby in the 1950s.
That would be the base case, unless someone could convince WR they had a better idea and deserved to be the representative body instead.
But it would have to be government with consent, and I really can't see that ever happening. Or it would have to happen without NSW, and possibly even Q'ld. And if they came along due to a lack of options, they would actively white-ant it all. Frankly, it would be an unholy mess best avoided if you didn't want to drag your comp down with it.
I had been wondering if there were precedents. The kicker of course is whether the 6 Nations and IRB can get agreement the Championship. The money on offer would keep Rats Arse on life support for quite some time - unfortunately. That doesn't bear thinking about. Those wankers might even use the money to prop up SR.