Sacraments are effective because people have faith, geez. We're probably not from the same world, but even if our worlds are somehow related, 40 thousand years in the future is still a very, very long time! There's a Church here too, you know, and even if it's not like the ones I knew back in my world, the faith and branch of worship is still the same. The equivalent in your world, Garviel called it "Cruxian", spelled "c-r-u-x-i-a-n", while it's known as "Christianity" here, making its followers called "Christian". It's phonetically similar, but the latter is spelled "c-h-r-i-s-t-i-a-n". Have you heard of that, at least?