Yes and no. I have read a number of studies and testimonies from seminarians, former seminarians, and priests that say dioceses who have orthodox bishops and most importantly orthodox vocation directors have a good (or better) number of seminarians.
The dioceses that have modernist vocation directors and/or bishops often have very low numbers of seminarians.
From what I’ve read this is for a few reasons:
- if the bishop or vocations director has a modernist lean, they have a tendency to turn away a lot of seminarian candidates who have a traditional lean to them
- if the bishop or vocations director has a modernist lean, the seminarian candidates may often decide to join a religious order instead of the diocese, petition to become a seminarian for another diocese, or decide against becoming a priest altogether
- if the bishop of vocations director has a modernist lean, they may send their seminarians to seminaries that are less stellar than others; which may result in an orthodox seminarian leaving his calling or leaving for a religious order or other diocese.
- finally, if the bishop or vocations director has a modernist lean, it will eventually infiltrate all the parishes which can negatively affect vocations.
For example, in my home parish & diocese (the one where I was baptized and confirmed, not the Archdiocese of Philadelphia where I currently live); their vocations office had a modernist lean. At one point, the diocese only has 3 seminarians, and none of them were actually from the diocese. However, my home parish, which has been a good parish in the diocese has 5 Deacons and has a number of priests come from the parish in my lifetime. But all the priests who grew up in my parish have joined religious orders.
Today, the diocese has 5 seminarians and is doing a better job.
So having good, orthodox vocation directors makes a huge difference.