South African cities and their multipolarity

So, I knew that South Africa's capital/city situation was a bit odd, but I never realized until today just how weird it truly is. Officially, South Africa's has three capitals – Cape Town is the legislative capital, Pretoria is the executive capital, and Bloemfontein is the judicial capital. It's unclear to me where Jacob Zuma, the country's president, actually lives, but he has official residences in both Pretoria and Cape Town. The parliament meets in Cape Town, however oddly enough, despite being the judicial capital, Bloemfontein is actually not where the nation's highest court, the Constitutional Court, meets – that honor goes to Johannesburg – which despite being the largest in the country, is not an official capital.

The largest and most important city not being the capital is actually something that's common throughout former British colonies. Washington, DC is not even within the top 10 American cities by population, Ottawa is only the eighth largest city/fourth largest metro area in Canada, and Wellington is essentially tied for second in New Zealand with Christchurch (Wikipedia seems to be confident enough that the 100 person difference is accurate, though).

At first I was going to say that this is due to their fluctuating populations, but now that I think about it, that's not the case with the US, for which, if I understand correctly, DC was a compromise between the North and the South after the Civil War. A lot of state capitals in the US are similarly insignificant – Sacramento in California and Albany in New York, for example. In fact, none of the six most populous US states have the same capital/largest city; not until number seven, Ohio, do you get Columbus as both the largest city and capital.