Xterm, I think, if I understand Archie's idea well enough, that the point of this idea is that a BotBr who submits a composition to the Darwinian thing knows what he's getting into: if the song performs poorly, it's killed. Nobody has to use it, but it makes for a fun way to introduce some stakes.
Also, what if periodically, say, each month or however long, the poorest-performing tracks would be placed on the Chopping Block, and BotBrs could listen to those tracks that were in danger of elimination. If they really liked one or more of them, they could somehow save them from execution, maybe by paying boons or something. And higher-level BotBrs could have more influence on how well the Darwinian tracks do.
All in all, I think it's a great idea.