alt Hacker NewsThere is only so much time in a day. Often singing in choir conflicts with playing sports because you have concerts and games on the same nights, so you have to make a choice. There are also schedule pressures - if you are going to get into college you nearly have to take math, English, science, and foreign language classes beyond what your school demands and that forces hard choices if there even is a class period free (don't forget you might be taking band to take up that space)
Finally, there are a lot of bad teachers. They are so interested in winning competition and teaching perfection - but for most music will never be anything other than a fun hobby and so they are getting the wrong teaching which turns many students off. I've seen a lot of award winning school choirs, and the next town over with the same number of students has twice the students in choir despite not winning awards - communities need to pick and often don't realize this.
In my secular chorus, we may have two main performances per season, but we rehearsed together for 2 hours every single week for months. We purchased polo shirts, and there was a dress code. Our dues covered operating costs and sheet music. Being a civic group for casual singers, our costs were kept low, but many choirs travel, double down on the costumes, and many people find it requires a high level of dedication, free time, and independent wealth. It is no coincidence that many members are retirees!
In church, a lector could prepare for 30 minutes and have a 5 minute speaking part at the Mass. The ushers and EMHCs also have part-time gigs. While altar servers are on duty for the entire service, they do not need to rehearse every single week. A church choir may serve for one or more weekend services, plus the 90-120 minute weekly rehearsals, and that's not counting holy days, Easter, Christmas. If you take a role as cantor, director, or piano/organ, expect to become indispensable! Some families just found it easier to join en masse so they could stay together.
Some chorus members are also secretly voice coaches, so if you protest "but I can't sing tenor" they may lovingly tackle you and sell you a package of private lessons.
I found it difficult to serve in any other ministry alongside choir, and you may find it difficult to hold down a job and/or family alongside a secular chorus role. As I said, high demand/great rewards.