M. Ted, I think our band is operating in a different world than you're describing, and as Dan said, it's all about context.

As a band, our group is less than a year old, so we're still building a core repertoire. We're amateurs, and pretty much in it for fun, rather than fame and fortune. We make decisions by consensus (or some approximation thereof); we don't have a leader/director, and I don't see us choosing one. We perform less than once a month and practice as a whole group maybe once a month on average (maybe more before a performance, and vocalists may get together more frequently to work on intonation of our harmonies), because of busy schedules with work and family, and because one of our band members lives two hours away from the rest. We're still at a stage of having something that works well in practice fall apart due to stage jitters, even with a cheat sheet in front of us. (Though I have to say our last outing went quite smoothly.)

A perfectionist might say we're not ready to perform, but it's getting that stage experience that helps us learn to get over the jitters, in addition to the improvement that comes with accumulating practice time together. You have to start somewhere.

So the conservative approach that Dan describes might not be necessary for everyone, but taken in context, it seems like a good idea for our band: dedicate a certain amount of practice time to polishing that fairly unchanging core of the repertoire, and have fun playing around with other songs and tunes with the rest of the time, exploring what might be added to the core. I think he's also responding to the earliest experiences of the band (before my time), where a core was never developed, new songs or tunes were continuously added and then dropped. Polish was sacrificed entirely to versatility.

Yeah, having only one decision-maker in the group would sure simplify things, but it would make it an entirely different kind of band.

This all has us drifting into "building band repertoire," rather than song accompaniment & tune accompaniment...
~ Becky