It just means will be high in demand, no need to read too much into it.
GHI, Banana, Pied were all game changers, no matter what your individual opinion of them is.
Alot of subtle morphs or less drastic morph compared to another such as sable or things like uncompatible hypo lines... were not as high in demand as the above, so not so much a game changer. Thus they are not in many collections even though they have been available just as long.