Ex StreetEasy dev here (from a long time back). Is this buying or renting? If it is renting then I would agree with you, the market is so commoditized in NYC for renting that the current broker structure doesn't make sense.
The best agents are really "only" good because they know of the good apartments it's not that the actual broker part itself requires some sort of special skills.
There is a reason why everyone who has the funds turn to buying real-estate.