Most people consider gaming to be something that's eating your time, money, and - if you exceed a certain level - even your health. There were even some extreme gaming cases leading to death, most of them happening in Asia. The interesting part is that we have a lot to talk about regarding gaming economics, and there are two sides of this story - the one regarding gaming companies, and the one about “gaming for money, " even though this is something that usually leads to your account to some MMORPG being terminated, if discovered. Today, I will try to reach both these subjects, although I don't have accurate statistics available. After all, there's the past to look at, and there's the global economic situation, so we'll try to look into the future. . .
There are people earning a lot of money from gaming, and you don't believe this until you meet one. I am not talking about professional gamers who usually have sponsors behind them, enter tournaments, and so on - those are only a few, but since there are probably at least a few thousands trading in-game items for real cash, even when this is officially forbidden, they are the ones to talk about.
To become one of them, you need to be very good at some MMORPG, of course. As far as I know, Lineage and World of Warcraft are the best choices for making money. Unfortunately, becoming very good with them takes some time, and - as I was saying before - this item trading thing is all about the gaming's black market, and once you get caught, you can say bye bye to your account. Considering these, best choice for you would be to talk with someone who did it already, because Google won't be able to provide the best answers to your questions, probably.
Next, and last for today, we have the “real game economics, " involving gaming companies, and hardware manufacturers. While the global economic cooldown lately started to look like a crisis in many countries, the gaming industry has its own problems, and most of them are related to the lack of originality and games under development that are being discontinued because there's a very strong competitor already on the market. If you read about the Midway shooting , you can get a better view of the situation, at least as it looks for some developers.
On the other hand, gaming companies have to handle the excellent opportunity that is the chance to enter emerging markets, and also the opportunity given by the age of this industry. Collectors editions and reissues of older games are also very interesting items for a lot of people, especially for those that grew up playing pirated games, and got to a point in their life where they consider that it's better to do it later than never, and would like to buy those games that took over their lives a decade ago. Obviously, this is leading us to the same markets that I mentioned above - emerging countries, but it's a fact worth being mentioned.
I guess this is all, but to get a better view of the entire gaming economics system, you need more than just to watch. You have to be there, play the games, talk with those working in the field, get to know better how the black market for in-game items works, in a word: explore! What I have done here was only to point you in the right direction and tell you what to look for, but the rest is up to you!