According to https://en.wikipedia.org/w/index.php?title=Monopoly_(game)&o... Monopoly was intended as a way to demonstrate that an economy which rewards wealth creation is better than one in which monopolists work under few constraints.
In other words and put much more harshly: Monopoly is played the right way if after a short time one player is happily winning and all the other ones are really angry.
I didn't see the connection until someone pointed it out to me when I was already an adult. All I have from this game is memories of boredom playing it with family as a kid.
Played correctly, Monopoly isn't a terribly long game, and (usually) once someone gets ahead, it is a fairly quick steamroll.
The Parker Brothers rules, rather. The game was a folk game before its acquisition by Parker Brothers, and their rules are a slightly simplified version of the Quaker variant learned by the man responsible for the graphic design of the published version of the game. House rules trace their lineages to versions of the game before Parker Brothers published it, and are equally valid. Although money on Free Parking introduces a ton of randomness, lengthens the game significantly, and is bad, it is no less real.
...for the monopolist. Everybody else is bored to tears. This makes it a terrible game in its more well-known form.
a) mechanisms to make the game proceed faster, and
b) to play the "follow-up" second ruleset, where (AIUI) you use something like Georgist rules (the land value tax) where players are supposed to realize, hey, you can't monopolize under the LVT because monopoly rents just get taxed away.