There is one major, major problem with this interpretation. He states over and over again that no hobbit has ever seen Tom Bombadil. But that's not true. At least one other hobbit has been described as knowing Bombadil--that is Farmer Maggot (the one Frodo used to steal mushrooms from). Let me quote from the story: "[Bombadil] made no secret that he owed his recent knowledge largely to Farmer Maggot, whom he seemed to regard as a person of more importance than they had imagined. 'There's earth under his old feet, and clay on his finger; wisdom in his bones, and both his eyses are open'" said Tom.

Later, it is mentioned that Bombadil already had messages from Gildor that Frodo & co were going through the forest.

I think the reason that Bombadil his hardly ever mentioned is the taboo which Hobbits have of going on adventures. If they talked about their adventures in the forest, meeting with magical folk like Bombadil, they would lose respectability.