That’s a very good question. I think it stems from a few things.
- Those who can sing and like to do it in a congregation or choir may not feel comfortable singing by himself/herself up there in front of everyone for all to see and hear.
- It might be a small parish which don’t have the kind of voices which would be good for chanting the psalm or are like those in No. 1.
- There may not be any musicians in the congregation and feel intimidated about learning music especially if the music director isn’t too nice.
- As a people on a whole, we’re not encouraging our children and our peers the importance of music and singing in the liturgy.
- Those who are trained musically may have found the music program at their parish not so great and a music director not open to expanding it or a pastor not wanting to do anything about the lack of a music program. So, they go to other parishes or find music jobs in churches of other denominations. If you aren’t a director or don’t have a flexible director, you can’t make something go from bad or mediocre to something really beautiful.
- There are some music programs which are “clicky” and if you aren’t in the click and they don’t like you for whatever reason, no matter how talented you are, you are either not going to be treated well, or you will leave.
- Some don’t want to commit to singing every weekend (which is the case in some parishes) when they might want to go away or attend mass somewhere else for a given Sunday. This is very understandable. I cantor almost every Sunday at the 12:15, but I am also paid for doing this, so it’s a totally different story. When I do need to be somewhere else, there are three other paid cantors that I can switch masses with or ask to substitute with.
I’m sure there are other reasons, but I think the lack of importance in liturgical music is a major reason. I don’t know any cantors who aren’t Catholic, although I have known cantors who should not have been cantors with voices that could peel paint, but no one else “stepped up to the plate” as you said, in their parishes.
I can understand a director or pastor bringing in a person with musical talent not of the Catholic faith, but is interested enough in the faith to want to volunteer her/his time and has a good amount of respect and understanding of the faith. When no one in the parish wants the “job” and if you as the pastor would like someone to chant the psalm, gospel acc. and other parts of the mass, instead of just reciting it, I understand bringing in someone from outside of the church.