Just having a flick through the stats provided, I notice that the key stat that is used to support the contention that the CC is more popular than Super Rugby is the average TV audience.
Average TV audience for CC = 466,388
Average TV audience for Super Rugby = 361,658
I don't find this stat at all surprising. I can't imagine there would be much interest at all in NZ or AUS derby games or games between NZ and AUS franchises. I expect that the bad figures for these overseas games would bring down the averages significantly.
What I think would be more relevant will be the average TV audience for Super games involving SA teams and comparing them with the Currie Cup stats. I also note that the (admittedly very little) I have seen of the CC this year has been played in front of very low crowds, whereas the Super games in SA had massive crowds.