Firstly. Political parties were not around when the Constitution was written. The founders didn't want political parties, they were a British import
Secondly. Why South Africa? since they ended apartheid, got rid of their nuclear weapons and did everything the international community expected of them South Africa has declined, it's no longer the gem of South Africa, and quality of life has reverted to the mean. Why would you make that your foundation? it's like saying American politics need to be more like Mexico
They live very comfortable lives with the current two party system. If we had one party only they would have to take responsibility for what’s happening. With a two party system you always have the other side to blame. With more than two parties you start losing power. The current system is just perfect for putting on a good show for the plebes to keep them fighting each other while the powerful pull the strings in their own favor.