Rather ironically, the Parker Brothers buying the exclusive rights to produce the game off of Charles Darrow was kind of a monopoly in itself. Which is especially ironic when you consider Elizabeth Magie's The Landlord's Game was designed to warn against the dangers of real-life monopolies. It wasn't supposed to be fun at all. It was supposed to be educational.
Magie was a follower of the economist Henry George, and designed the game to be a "practical demonstration of the present system of land grabbing with all its usual outcomes and consequences". She wanted to show how rents enrich property owners and impoverish tenants.
Instead, it turned friendly people into crazy capitalists and divided families. Where did it all go wrong?