Indeed, the Myerson-Satterthwaite theorem from mechanism design implies that no mechanism for bilateral trading can be perfectly efficient.
My understanding is that there has been research into mechanisms that can reach some kind of constrained optimum, but the problem is complex enough that even these mechanisms are not considered to be feasible.
no mechanism for bilateral trading can be perfectly efficient.
Yep, but this illustrates how bad it can get!
Indeed, the Myerson-Satterthwaite theorem from mechanism design implies that no mechanism for bilateral trading can be perfectly efficient.
My understanding is that there has been research into mechanisms that can reach some kind of constrained optimum, but the problem is complex enough that even these mechanisms are not considered to be feasible.
Yep, but this illustrates how bad it can get!