"[T]he advantage is that they're a heck of a lot more consistent and pay much better attention."

This implies that the only reason for garbage collection is programmer fallibility. However, I think there are some cases where there is literally no better way of knowing when everyone is done with a piece of memory than by checking (closures strike me as an area this can happen pretty quick), at which point the only solution is automated garbage collection - be it provided by the runtime, a library, or written by the programmer for the particular program.