This means IMHO that the Pope didn't engage his infallibility in the promulgation of the NO.
I hope you're right, but I don't think that's the case, this is the context of the words stating the rite is not a "dogmatic definition".
Paul VI's words:
They might come to believe that the equation between the law of prayer, lex orandi and the law of faith, lex credendi, is compromised as a result. 11. It is not so. Absolutely not. Above all, because the rite and the relative rubric are not in themselves a dogmatic definition. Their theological qualification may vary in different degrees according to the liturgical context to which they refer. They are gestures and terms relating to a religious action
What Paul VI is saying is that a rite is not a definition of dogma
, but a liturgical expression of worship
. I'm sure he was anticipating the criticism that the rite would sustain for the ambiguity with which it abounds. These words are true, but how does it justify anything?
This audience is just an amazing collection of non sequiturs. When juxtaposed with the reality of the NO and the results it spawned, it is utterly stunning. It saddens me that it was uttered by a Supreme Pontiff.