Video games are, by nature, broken economies. Especially MMOs. Why?
Most modern video games, and all MMOs, have an unextinguishable supply of money.
Kill something and it drops money, it respawns, you kill it again, it drops money again.. etc.
A video game could be created without a broken economy, if the game did not respawn and all merchants had a finite amount of money that once it was gone, it was gone. However, this cannot be done in an MMO, for obvious reasons.
The difference though, is that a game like Skyrim, you're spending your money until you "beat" the game, then in theory you're done.. if not, well it makes sense for you to have more money than god, since you've saved the world, slayed dragons, etc. and are now wandering about being a weirdo.
In an MMO though, people play for years.. and what this does is it breaks the economy in a different way, I'll use City of Heroes as an example, since I played that one long enough to see the economy change:
When I started, 1 million influence (money) was a LOT. People would run costume contests (a staple of City of Heroes), and prizes would be from 100K to 1M. As of shortly before the shutdown announcement, money was.. uhm.. worth a lot less to us higher level people, we would routinely spend several hundred million influence to equip a character- and that's not even considering the extreme powergamers who would spend several billion.
The last costume contest I saw, I think the top prize was something like 500M influence.
The problem with this is, in MMOs the economy changes.. but the drop rates don't. So if I started playing WOW now that CoH is no more.. I would be going in to it after 8 years of economy frelling, so I would be super poor, by comparison.. Unless of course I was able to find some method of making money off the super wealthy high levels.
MMOs these days use what's called a 'gold sink' to try and prevent the economy from becoming too frelled by forcing high level players to spend lots of money on .. something, but those only work a small amount. Most MMO players, once they figure out how to make money in their MMO.. they contribute to the further breaking of the economy, even if not intentionally.