I'm often in areas that have no or very limited internet access. So if it goes to Lightbox or some other steaming service, I guess I wont be seeing the 2019 RWC. I loose.
Speculation is that Lightbox would look to offer it on mobile. Spark mobile subscribers get free Lightbox - and something like 30% of streamed viewing is via non-TV devices.
And with TVNZ as the prospective ad-funded partner then you'd still get to watch some games terrestrially.
So you dont lose - at least at this speculative stage.