I guess the question is how do investors know an idea is "obviously good"? Did anyone/everyone know that the pagerank algorithm was "obviously good" before they tested it? And if it was - did they build it/think of it in one day?
Famously Yahoo turned down Larry and Sergey when they approached them with the idea - they didn't want it before it had proved it's worth. In other words: they wouldn't invest in an idea.
His business model is that you can put your idea on his website (for a nominal fee of $175) and he will then try to sell or license it to someone, and you split the proceeds. Obviously it is in his interest to tell you that he has had tremendous success himself. Besides, I think the $175 will make him a good amount of money from naive hopeful inventors.
like mix max says he's "worked in the basement for years": his reputation and relationships took many years to build, and typically he sells legal licensing to use his ideas...; this is beyond "just an idea"