Most clergy will say that their modern approach to liturgy and catehesis is working because their Masses are full. What they fail to realize is that those who attend Mass may not be very well formed as Catholics. They support same sex marriage, abortion on demand, women clergy and any kind of creativity in the liturgies of the Church and its music. In other words, these people are all over the place but remain "cultural" Catholics who like the sense of belonging, regardless of what is experienced or taught.
In addition to this, most clergy refused to acknowledge that even in a parish with well attended Masses, that group only comprises 10% to 30% of the Catholics in the area. In other words about 70% to 90% of Catholics are disengaged.
Thus this truly good news from FSSP parishes (completely in union with Rome, not the SSPX) tells us that the Catholics that are going to these parishes are Catholics who want to be Catholic, a no nonsense Liturgical life, strong beliefs in the Real Presence, male only clergy, pro-life and Holy Matrimony between one man and one woman and if lawful (sacramental) for a lifetime!
I copy this from the Deacon's Bench: