Never.
World Rugby has pretty good grounds for claiming ownership of the name "rugby", and the IP that attaches, no matter how painful that is.
For all the outrage, the name is the issue at stake, and they do have very deep pockets. I am honestly buggered if I know why this is a battle worth wasting time and money fighting?
To me it has always seemed like RL was just having a self-righteous tantrum...
We gain next to nothing from keeping the word, cause an assload of pain for ourselves and any progress RL actually makes is benefits RU, because to 99% of the world "Rugby" and "Rugby" are the same thing. (the fools.....)
The only logical explaination i can think for why RL clings to the word is a childish sense of honour, "we have just as much right to the word as they do, and they should respect that. Wahhhhh"
Personally I would go with 'League XIII Football' it can then be Footy, XIII or just League depending on your regional preference.
Keeping the word Rugby is holding our sport back. It keeps us in a war we can't win and if you try to introduce people to Rugby League they are not interested as they think it's Union.
Im personally in favour of jumping in with
Gridiron (its already an umbrella term for half a dozen codes, why not us too)...
For the history nerd, it does make sense: 15 years after Walter Camp proposed rule changes to Rugby in American Colleges, Northern Union introduces the exact same changes. I find it hard to believe that is a coincidence; more likely word of this revolution travelled across the Atlantic and were taken on by the NU clubs.
Gridiron Rugby seems most natural (and i reckon it would be much easier convincing people it is an independent sport instead of another Rugby league [see what id did there , post: -)"]), but if we wanted to get away from Rugby entirely we could do
Australian Gridiron or
IIIX Gridiron or any of a thousand other choices.
If we are going to ride someones coattails, why not the biggest sport on the planet (it might even be a way to get RL into the American market as a kid friendly variation of AF). And its not like we will be confused with NFL like we are with RU...