When the United States was formed it was more than 60 years before the development of the modern corporation. No accommodation was made for corporations or similar institutions to have representation.
Corporations and similar associations, like industry organizations, have genuine interests. A University has the interests of its students, faculty and alumni among other groups, that need representation in those capacities. The same is true of an auto manufacturer or a duck hunting club.
How do these entities get representation in a democracy and how are the conflicting interests mediated?
Right now, these entities have two modes of influence in the political process. They hire lobbyists and they contribute money to campaigns. Unions also provide manpower to the Democrat Party directly.
So how should commerce be represented?
My answer is that citizens should have one mode of representation and commerce should have another.
The House of Representatives should have no funding or money representation. That means selecting legislators by a random process. Sortition. See my book on the subject here.
The other house, the Senate, should have open elections with money and every other form of commercial pressure, including unions, having full access.
The reason for separating the two houses is to give actual individual citizens a form of representation that truly represents the citizen quality of the population. A citizen exists in many dimensions, only a few of which are commercial. Citizens are parents, artists, sexual beings and much more.
We need corporate and institutional representation but we also need pure citizen representation.
(The photo is a kleroterion for Greek random selection).