NLM has some very good analysis on the statement by Cardinal Castrillon Hoyos. Read it.
Clearly then the Cardinal is not speaking in terms of mandatory requirements, he is speaking in terms of what is to wished, hoped for, worked toward and which is desireable.
This is important to clarify for two reasons. On the one hand, it continues to contradict the assertion that some would make, suggesting that "extraordinary" is meant just as it is with Extraordinary Ministers of Holy Communion -- a rarity or occasional exception applicable only to particular circumstances. This is important for the usus antiquior is not to remain marginalized. Both for its own sake and for the sake of the modern Roman liturgy, it needs as wide a dispersion as possible, even while the modern form will remain the statistical majority of liturgies presently offered.