For 99% of human history, you needed to already be rich in order to buy an ownership interest in a prosperous business. Even in old timey England, individual property could not be divided into more than a dozen ownership pieces. If you wanted to make money from a business, you had to possess enough capital to purchase it outright.
The United States did its part to break to break ownership positions into smaller increments by making “share trading” and liquid exchanges a major part of its economic activity. These smaller share increments also had the reciprocal benefit of making it easier for companies to cast a wide net when raising capital that could be used to advance growth at a much faster rate than would be possible if only select financiers could provide the capital.