That's a good point. I thought about it some more, I think we would end up with trusted idea 'editors'. Folks with no reputation would be forced to go to these high-reputation editors to resell ideas. These editors would gain reputation for their excellent judgement of ideas which they publish and sell.

I think you're right though, good ideas don't come from people with a few consistently good ideas, they come from people with thousands of ideas and the right filters in place.