You have three options:
1) Get working in the games industry and hold on to the idea. Once you are an established team member and have honed your skills you might get a chance to take your idea and run with it. Be prepared to wait a long long time with no guarantee of success.
2) Start your own company. The game will probably have to be unambitious technically to get it out the door. If you are lucky and it succeeds you might get a chance to make the game you really wanted to make as a sequel.
3) Become a pig-headed self-obsessed git with no inter-personal skills, technical knowledge, artistic sensibilities or management skills. Develop your fawning and butt-kissing techniques to a high level. You are then in the perfect position to take on a project lead role in a games company from where you can marshal a group of highly-skilled but lowly paid workers to do your every insane bidding.
I'd go for option 3. As a side benefit you get good parties, chicks and drugs.
Joe