CC and other significant well attented local competition revenue streams outside S15 and Tri nations. Australia have? Blathering = other options.
I don't know for sure, but my guess is most revenue comes from TV rights generated mostly by the super rugby comp and possibly 3N. SA simply will not give that up unless there is a serious replacement. Australia have NZ right on their doorstep and I don't think they'll have a problem with a Super10 format against their neighbours. Possibly even including a PI team or two. The tournament
will miss the SA revenue that's for sure, but I think they could make it work.
SA have the option of Europe, but firstly the NH rugby calendar is full already, it will mean major restructuring. Secondly, SA will go backwards if we join Europe. There is a reason the SH teams are still dominant internationally. And on top of this, even though it's the right time-zone it's still 10+ hour flights and I'm not convinced Europe want that. One of the strengths of their comps is that all games happen close enough that fans can travel easily.
Things may change in the future, but for now SA's best rugby interest lies with SANZAR.