The Democracy of the founding fathers was Greek Democracy, predicated upon a slave society, and restricted to only the elite. This is the society we live in today, even with our reforms towards direct representation. The system is inherently biased towards the election of elites and against the representation of the masses. Hamilton called it “faction” when the working class got together and demanded better conditions, and mechanisms were built in (which still exist to this day) that serve to ensure the continued dominance of the elite over the masses. The suffering of the many is intentional. The opulence of the wealthy is also. This is the intended outcome.
In practice, the dominant player in the industry can operate at a loss to drive the upstart competition out of business, buy their assets for pennies on the dollar, then jack their prices up again when there are no alternatives. Or, if you don't like that one, choose any of the numerous anti-competitive strategies in use today.
If people collectively saw that behavior and said "We're not buying from you anymore", they could put that company out of business, but that simply isn't realistic when dealing with such a large number of individuals. So it continues to work.
Without regulating anti-competitive behavior, monopolies are inevitable and competing without an initial bankroll capable of operating at a loss for as long or longer than the existing monopoly is impossible.
The idea is cool in theory - that anyone who doesn't like how the current monopoly is operating can simply open their own competing business, be more consumer friendly, and steal the market share - but that's simply not the reality we live in.