> If you want a reasonably efficient market, you need some participants to have close to perfect information.
I don't think this follows at all. It isn't clear that if the assumptions are almost true the outcome reasonably close to that if the assumptions were true.
Even if it does hold true remember that economists view monopolies as perfectly efficient solutions but that in that scenario it is efficient because the monopoly captures all the available value not the consumers. I also believe that the maths behind the efficient market hypothesis break down if its assumptions don't hold.
I don't think this follows at all. It isn't clear that if the assumptions are almost true the outcome reasonably close to that if the assumptions were true.
Even if it does hold true remember that economists view monopolies as perfectly efficient solutions but that in that scenario it is efficient because the monopoly captures all the available value not the consumers. I also believe that the maths behind the efficient market hypothesis break down if its assumptions don't hold.