I find this hard to believe.
Spur, Jimmys, Adega and even Europa are all quite expensive.
A decent steak at Spur with a portion chips will set you back around 90 rands.
The problem is not price, cause most of the folks in north JHB can afford R140 per plate.
There is just no interest in fine-dining (although some Muslims do chow at haraam fine-dining outlets) OR there is too much support for franchises.
Perhaps that oke Ozzie from Master Chef can open one restaurant up. I'd pay to taste some gourmet food he prepares. Based on price, it would probably be around the cost of Spur/Jimmys/Adega, but taste much nicer.
@OP:
There isn't much in PTA East. There's a few halaal places in Hatfield, nothing in Brooklyn and I think the Chicken Licken in Menlyn is halaal.
But (as I mentioned above), there is mostly halaal franchises and Pakistani "fine-dining" (which is a bit ironic, especially if you spot the cockroaches in their kitchens

)