Earlier quoted context omitted.
I think all available evidence points to active investors NOT being good at guessing the future, when compared to the general consensus. The second half of your argument seems like an interesting opinion, but I'm curious where the evidence is for it.
What do you mean by "general consensus"? If you mean "current market values", then those are being set by the aggragate opinions of active traders. If there are less active traders, there is less brainpower being devoted to finding this consensus, so it would be suprising if the consensus did not get less accurate.
I don't really consider it possible for pricing to be "accurate". It is what it is, but accurate implies there's a correct valuation, which I don't think there is.