Two important factors you're leaving out: (1) Does the intermediary add value? Sometimes they do, by facilitating better market functioning. If I sell a house

Two important factors you're leaving out: (1) Does the intermediary add value? Sometimes they do, by facilitating better market functioning. If I sell a house and a real estate agent has access to a better buyer pool than I do -- likely, as they've been doing it for a while -- then I benefit with a higher selling price and the agent gets a commission. The loser is the "deal hunter" buyer who sits at the low end of the market, looking for a "deal" due to something being mispriced. In some markets, e.g. public market trading and low-end insurance, it's easy to get the same benefits with a computer. On the higher end, however, like with complex business insurance, I'd gladly pay a middleman a few % to help me get through the complexity of picking out the right package, coverage, helping me think through the risks, etc. (2) Are people afraid of doing it themselves? When dealing with a large enough proportion of wealth, some people will demand assistance, even if very expensive. I see this dynamic all the time in real estate. Most people don't want the hassle of selling a house themselves and would rather, somewhat lazily, just have someone else deal with it.