If RL was in a good place in Australia then I might a agree with you, but at this point RL is f**ked in more than half the country. So how about the NRL look after it's own backyard first before it tries to save the world.
I also don't necessarily agree that making more and more other nations dependant on the NRL by "investing" in them is actually a good idea or will actually lead to more interest in internationals in Australia.
1. The state of RL in half the country is due to the same apathy and arse-backwards short term thinking that cripples international RL - for the purposes of this discussion, WA and SA may as well be other countries.
2. I said invest in the game, not hand out money willy-nilly to random nations.
An easy starting point would be not plonking Origin in the prime calendar space for internationals, for the slimmest of vaguely possible benefits to the NRL.
Followed by having the Australian team play more than 1 game a year.
3. That said, strategic investment in the sport in a selection of other countries (and Australian states, for that matter) would result in not only improving their international standing and the international game, but from a selfish perspective has obvious benefits for the NRL. More fans, more players, more potential broadcast deals.