[jawns]

The choral world has survived despite a longtime shortage of castrati.

I'm sure they'll figure something out.

In all seriousness, SATB is mostly a constraint because of how choral composers write their music, not because good music demands it. You can produce beautiful music without all four voice parts being equally represented.

[CGMthrowaway]

Castrati never mattered for choruses - you just use a large choir of boys. They were important for opera/theater, where you need a single voice with enough power.

[pclmulqdq]

I compose music once in a while. I'm now trying to write more in a texture like SSAATB if I want amateurs to sing the music, but it's not as easy to write as SATB or SSAATTBB music.