But that's the problem. You know why? Because anybody can do this. You can have one million people do this, for one million years, and you know what you'd end up with? Nothing.
Don't get me wrong, it's great that you also attach careful research to your idea, but that only serves to lessen the risk you've overlooked obvious reasons for it to fail. It doesn't mean it won't fail. If your idea was guaranteed to succeed then crossing over into development wouldn't be a problem. You'd be able to get the money somehow. I know many ordinary people who have set aside as much as $50-100K just by being focused. Or you could get investment, or a SBA backed bank loan. But idea people won't actually work to do these things, because they know the truth: their idea may end up failing (being worthless when actually tried). Either that or the other truth: even once an idea is developed it takes time and effort to grow it into a success.