That's silly you can say that about a lot of things. If a large company builds its headquarters in a place that is going to have 'positive externalities' on the surrounding area too but that doesn't stop companies from locating their employees together in buildings because they are worried they might benefit other surrounding businesses.

Roads as with anything have a symbiotic relationship with the nearby community. If there are no places people want to go along a route then people won't use it or pay tolls conversely if there is no road to get to a business no one will go there either.