Yet the game's inventor, Charles Darrow, was convinced they were wrong, so, in the height of the Depression, he made 5,000 copies of the game and marketed it himself. Monopoly was an instant success. Parker Brothers reconsidered and marketed the game in 1935. They sold more than a million sets within a year and Monopoly went on to become the world's favourite board game.
That's the official story, anyway, and the reason for this week's 60th anniversary celebrations. It's a classic all-American rags-to-riches tale of Darrow, an unemployed heating salesman, who sketched the board on an oilcloth that covered his kitchen table and used the baubles adorning his wife's charm bracelet - a top hat, a dog, an iron, an old boot and a thimble - as the counters. But the true history of Monopoly is longer and murkier.
The tale begins with an American economist called Henry George who propounded the "single-tax theory" that property speculation lay at the heart of the economic problems of the nation. One of George's students, Elizabeth Magie, created an entertaining diversion to demonstrate the evils perpetrated by unscrupulous landlords. It was a game, played on a square board with 40 marked sections around the edge. There were streets, railways, and even a square marked "Please Go To Jail". Players threw dice and moved counters round the board, paying forfeits and rent according to where they landed. It was called "The Landlord's Game" and was granted a patent on 5 January 1904.
Elizabeth Magie's game became popular among her friends, though no attempt to market it was ever made. Unfortunately for her original intention, she discovered that people liked playing it not so much for the salutary lesson it taught them about the evils of capitalism, but because they liked accumulating property, collecting rents and beating their friends and family. By the Twenties, the growing circle of players, many of whom were by now calling the game "Monopoly", had added new rules to allow investment in properties - a forerunner of today's houses and hotels - and Ms Magie was granted a new patent incorporating rule changes which she could hardly have approved of.
By 1933, when Charles Darrow was first shown the game, it was more or less as we know it today, even down to the Chance and Community Chest cards. His genius was not in inventing the game but in improving the design of the board, borrowing his wife's charm bracelet, and realising the huge potential it had. The true history came to light in 1935 when Darrow himself applied for a patent on Monopoly. The patent authorities first discovered a strong similarity with "The Landlord's Game", then unearthed another game, also copied from a version of Magie's original, called "Finance" which appeared in 1929.
Perhaps fearing that Charles Darrow, for his apparent plagiarism, was in danger of going to jail, moving directly to jail without passing Go or collecting $200, a Parker Brothers lawyer rapidly bought up all rights to both The Landlord's Game and Finance, breathed a sigh of relief, and got on with the hugely successful business of distributing Monopoly around the world.
In the spring of 1935 they sent a copy to Waddingtons in England and were astonished, a few days later, to receive a transatlantic telephone call. It was their first ever call from Europe and impressed them so much that they sold the British rights to Waddingtons immediately. The only changes that had to be made were to substitute pounds for dollars, London street names for those of Atlantic City, on which the American board is based, and railway stations for railroads.
Monopoly is now published in 25 languages - but still banned in North Korea, China and Cuba. One of Fidel Castro's first acts on taking power was to ban Monopoly and seize all the sets on the island.
Worldwide, over 160 million Monopoly sets have been sold, including a $5,000 set made by Alfred Dunhill and a $600 edible set, with all the components (including the board) made of chocolate or butterscotch. In 1975, while the US government printed $22bn of real money, Parker Brothers printed $40bn of Monopoly money.
With such economic power behind it, the Monopoly lobby can be fearsome. In 1972 the city council of Atlantic City announced plans to change some street names including two that appear on the Monopoly board. The president of Parker Brothers wrote to the commissioner of public works warning that such an act "could possibly shake the foundations of American tradition". He was probably joking, but the city backed down. Now, at the corner of Boardwalk and Park Avenue (the Mayfair and Park Lane of the American game) you can see a plaque to Charles Darrow.