Intuitively, the bottleneck is always the "getting things done" part, not the "idea" part.
But quite a few people limit themselves to one idea in many situations, which is bad. They don't consider alternatives. The quality of a course of action usually improves if you consider alternatives prior to its implementation.
More ideas could actually help on an individual level. Not necessarily on a social level though. Especially since the transfer of ideas is costly and often incredibly redundant.