When I went to Catholic schools from the late 1970s to the 1980s, about half the teachers were in religious orders, half lay people.
My cousin goes to Catholic schools right now. None of his teachers thus far have been religious, all have been lay people.
Such a shift in the past half century, along with other trends, is bound to affect religious devotion.
The Internet probably has an effect. I think the effect it has is one of degree. Years ago, people seemed to be divided into fundamentalists, and those who might doubt, say, that Joshua made the sun stand still in order to prevent sundown so that the Israelis could defeat the Amorites, or that the pope as Vicar of Christ speaks infallibly on matters of faith, and so forth. On say Reddit's /r/atheism there are so many secular people, that doubting people become complete atheists as opposed to moderate or liberal Christians. Those who doubt stop believing things completely, whereas in the old days they may have stuck around and been part of a church's liberal/moderate wing.
There also seems to be a counter-trend where those who stay in the church become even more fundamentalist. Michael Harrington wrote about this in "The Politics at God's Funeral". It creates a cyclical effect - as the moderates leave, the fundamentalists make the churches more and more fundamental and fanatic, driving out the moderates still left, which gives the fundamentalists even more power and the church drives out those moderates still left and so on.