There was one for sale here in Constantia as well; I saw when I was going through listings once. It's been removed but you can see it here:
I don't think the sellers really care about densification, it's probably sold out of necessity or it's simply not needed. If your income is taking a knock (lots of people's investment income is drying up) and children are out of the house, why do you need to continue paying rates for something that you don't need? And let me tell you about rates in these areas, I recently saw a house with rates of R26800 a month.