I'm going to disagree. Cricket is big in SA, and millions watch Proteas matches, but franchise cricket, no so much. Stadium attendance are down in all 3 formats, news channels barely cover it, except for finals, and it doesn't 'sit' at the same level for sports fans as Currie Cup rugby or PSL football. Maybe it's because SA's best players hardly play for their franchises (this effect can be seen in the Currie Cup) or something else, but franchise cricket has not been a ratings success.
It's sad, since I'm a big cricket fan, but people simply aren't tuning in. I still go to Warriors games, but St Georges park is lucky to see more than 5 000 people for a limited over match. For a 4 day match, with free entry, they are lucky to see 50.
As for Supersport losing rights, this was always going to happen with new broadcasters. Only a few people seemed to understand it though. Supersport lost their rights to Bafana friendlies too, and Starsat have that now.