Gamers are spending hundreds of dollars on their PCs or consoles and then hundreds of dollars on games every year, why would they need opportunities to earn some pennies? People play games to relax, not to earn money. When a game is turned into a job it stops being a game, it becomes a boring grind.
I will take mmorpgs as example, because this is the kind of game which has the most complete economical system where the real world trading mechanism better works.
There are gamers and gamers, or as some may prefer to say: "farmers". Some people play online games for status, achievements, while others join to farm some income. That is what already happens in some mmorpgs. There are people playing those games only for money right now, although they have spent a long time of their childhood and adolescence on those games for fun. Things change within time and something that used to be a leisure activity may turn into a job.
There are already enough markets for games that doesn't feature real-money trading directly, and the small minority of players that wants it uses them, so blockchain games aren't exactly revolutionizing anything. This is a typical case of blockchain devs having no idea what people want and need, and just trying to fit their "revolutionary technology" when no one asked for it.
I believe blockchain games are just legalizing something that is usually illegal in mainstream games. By the terms and conditions of online games you don't own your account, the game lends it to you instead, so everything you have in your inventory doesn't really belong to you. Blockchain games are fairer with players regards this subject, as you really own what you have acquired inside the game and can do whatever you want with those goods. I don't consider it a revolution, just a very welcome feature for players who can be finally rewarded for the time spent on those games (since repetitive grinding has always been a major part of such games).