the earth is growing and pangea theory is kind of a joke. the continents are not drifting around they are fixed in place. but as the earth is growing it stretches and distance between them increases.
Among other things If the size of the earth has been constant through time and all the landmass was clumped together one time then it would have been landmass only on one side and ocean only on the other which would have caused the center of gravity to shift which would have caused the oceans to shift and reveal land on the opposite side