Here is a fascinating interview – translated from French — with Fr Claude Barthe, a French Catholic priest, ordained by Archbishop Lefebvre and now regularized. Journalist Daniel Hamiche interviewed him for Monde et Vie 832. An excerpt, but it is worth reading the entire interview.
I think first of all that it is totally unrealistic to believe that we can wave a magic wand so that all Masses are celebrated according to the former usage in every parish in the world. However, I note – with many others, some of whom are very high placed – that the missal of Paul VI contains an almost infinite possibility of options, adaptations and interpretations, and that a progressive, systematic or systematically progressive choice of the traditional possibilities it offers, makes its “re-traditionalising” possible in parishes, and quite legally (according to the letter of the law, and its spirit). This is a simple fact: of many parish priests (I have already compiled a quick list for France, which I am careful not to publish, but which is impressive) practicing this reform of the reform, often in stages, and in the vast majority of cases also celebrating the traditional Mass.