Unfortunately there's not a lot the ARU can do in the short term to stop the exodus. When a French club can afford to pay a Shute Shield player, who also played a few NRC games $140,000 a year it's just an impossible task. There's simply not enough money in the game in Australia, NZ or SAF to keep everyone here. In the medium to long term the plan needs to be to bring more money into rugby in this part of the world.
Without rehashing everything that's been said over the past few pages, one idea is to improve the standard of rugby for the 6 Pacific Nations Cup countries ( US, Canada, Japan, Tonga, Samoa and Fiji). Over time this might see teams from those countries involved in Super Rugby, which further down the track would see their international teams improve. Rugby is going quite well in the US and a professional league there might not be far off and Canada tends to follow the US. We know Japan already has plenty of money.
IMO SANZAR should be looking at forming a loose alliance with the PNC (Pacific Nations Cup) 6 for mutual benefit. Long term, SANZAR, Argentina and the PNC (Pacific Nations Cup) 6 could generate enough money to keep most players in their own country. But it's probably 15-20 years off if it happens at all.
Rugby would be much the better for such an eventuality - 10 countries involved in international and provincial rugby and all competitive. It's a dream, but nothing ever happened without people coming up with what at the time seemed like far-off dreams.
I'm always the optimist.