We'd have what we have now - because PPVI ignored Quo Primum as if it was never issued and did not exist.
No, PPV never created a new rite - he restored it to it's original. The Law of Quo Primum was established to protect the Mass forever, to forever preserve the Liturgy he restored - just as it says in Quo Primum.
You misunderstand me. Let me rephrase: If Pius V had not issued
Quo primum, would there be any grounds for a priest to refuse the NOM? In other words, is the right to the traditional Mass only based in
Quo primum, or does the right exist indepedent of
Quo primum?
Furthermore, St. Pius V did not restore the rite to "its original," which is patently false from a historical point of view, nor did he claim to. The Latin says:
ad pristinam Missale Sanctorum Patrum normam ac ritum restituerunt. It does not say "the original;" the word is "pristine." Moreover, the Holy Fathers referred to are not what we call the "Church Fathers." Rather, it refers to more recent times. This can be confirmed if you compare the 1570
Missale with the
1474 printing.