Crowdsourcing also requires a tribe and/or media connections to have any sort of success. This is especially important for this idea which is not cheap to make.
But as per the OP, they are effectively looking for an agent.
In this particular case, I would believe them to be looking for a business development manager or something similar (someone to make their case).
As far as I understand the opening post:
- There is no "they", only an "I"... which I understand as "there is no team, only me having an idea".
- "Selling the idea" doesn't have to mean "I want to pitch my idea to an investor to see if we can reach an agreement that will allow me to go forward with my plan, hire professionals and develop the game while keeping the investor happy"... it could also mean "I had an idea I think is great and now want to sell it to someone who will pay lots of money for it".... granted, the rest of the post makes it sound different, still, not clear to me.
To the OP: I think you should clarify what it is exactly you are looking for.
- Are you looking for an investor? (Possible, but quite hard to pull off even if you are a known name in the industry. Without that, try crowdfunding or forget it)
- Are you looking to sell your idea? (not going to happen. Ideas are not worth a penny, everyone has more than enough already)
- Do you have a team already? A studio of professionals that could execute your plan given you get the money? (that makes the pitch way easier)
- If not, do you have any expierence in the sector? Are you a game developer already? (if yes, why not start building your idea in your own time with your own money?)
If you have no money, no name in the industry, and no expierience, then all you can do is start to become a game developer. learn the ropes, and become good enough to produce a prototype of your idea. Will take you years, but given enough dedication you will get there. With the prototype you could try crowdfunding, MAYBE look for an investor. Going to be tough without being known in the industry.
If you have expierience already, but no money and are not known well enough, build a prototype. If you cannot build even a simplified vertical or horizontal slice in about a years time, your game is way out of your realistic scope. Nobody will give you 100k$ as a nobody to build your dream game. You might be able to get some 10k$ from crowdfunding if you manage to create an awesome prototype and a good marketing campaign. But you will have to to A LOT of legwork for it, on your own time. Better start now, or redimension your project if you cannot pull it off without spending 10 years on the prototype alone.
If have the expierience and are already well known, well, then you wouldn't ask this question, right?
EDIT: After a quick glance at the "GDD" you posted there, I have to say this is nowhere near enough information to really pitch the idea to anyone.
Some story and high level game logic concepts is NOT a GDD yet. There are a ton of additional details that are very important to gauge the magnitude of the project:
- 2D or 3D?
- Graphics: AAA? Simplified or stylized? Costeffective or photo realistic?
- What do you plan for sounds? Are you thinking of voice acting, or keep costs down by omitting it?
- Give me a Elevator Pitch of your game that makes it crystal clear what the game is about. I don't care about your idea for a single level ("earthquake"), what is the game about exactly? Genre? unique selling point?
And so on... if you want to pitch, your GDD needs to be able to answer all the question investors will be having. On the other hand, you need a VERY GOOD elevator pitch to even capture their interest enough for them to give you a chance to pitch.
Nobody will read your GDD unless he is already hooked to your idea... you have about 1-3 sentences to hook them until they stop listening. Make these sentences count.