I originally asked this on /asksocialscience and received not even an attempt at an answer or direction on what to read. I considered posting this on /economics but text posts seem to not be an option and the sub is much more geared to current events (and ideological bickering from visitors of /libertarian and /politics). Most of the people that could adequately answer my question reside in this sub anyway so I was hoping that I could get an answer or direction in where to search.

If I understand correctly G-S states that in the absence of complete markets and perfect information markets are not even constrained Pareto efficient, meaning markets are chronically inefficient. However in Edgeworth's limit theorem he proves that as the number of traders approaches an infinite amount the set of allocations that are improvements shrinks to zero. So as I understand it, a Pareto efficient allocation will be attained regardless of information and incomplete markets given an infinite number of traders. I know that these theorems can't contradict each other so what am I understanding incorrectly? As an additional question, how efficient can we say markets are?