Why dont the present shapes of the continents fit perfectly into a supercontinent

The reason why the shapes of the continents as of today do not perfectly fi into to super continent because long time ago the super continent was scattered into pieces. And as times go by, those smaller parts of super continents undergo soil erosion caused by the water and other way that causes their original shapes change.  

Iwould choose the same momentum because if they throw a baseball very light and not hard at all then doing it with a bowling ball won’t hurt that worse