Every single game developer, programmer, artist, QA tester, and gamer has a dream game idea they are sure would be the best game ever. Ideas are a dime a dozen.
Even if you have an amazing demo, you are very unlikely to get any funding even with a solid prototype. You’d need something closer to a vertical slice of what the final game could be like in order to get publisher on board, and that’s still unlikely, especially if you haven’t made a game before.
And even if you actually manage to make this amazing game, marketing is half of what makes a game successful, are you actually going to be able to sell this game and get at least 10,000 people to look at it?