I think the counter-artument to jalopy's point is to compare the relative degree of investment by "informed traders" vs "efficiency providers" (market makers, H

I think the counter-artument to jalopy's point is to compare the relative degree of investment by "informed traders" vs "efficiency providers" (market makers, HFTers, etc). I think you'll find that investment by the former vastly outweighs the latter indicating that investment in efficiency providers is very unlikely to be too high.