It suggests that there are not enough people to make it worth the while of someone to be in that business. In that sense it is not like the market for horses (f

It suggests that there are not enough people to make it worth the while of someone to be in that business. In that sense it is not like the market for horses (for specifically) transportation. For that your statement would be true. For stocks I would argue that you need a certain critical mass of customers to make it worthwhile to be a stock broker. Let's use the travel agent example. There are people that would like to use a travel agent located at their local shopping center. Back in the day there were enough of those people that a agent could be busy and therefore afford the overhead of a business to service them. Now there are not enough people so the agent is not in business. However that is not because the travel agent does not provide value (what you are claiming for the stock broker). It's because there are not enough people that the agent can earn a living doing so. So it's not the value in this case (although it might be in other cases or for other things).