Sure is a lot of Fenn-bashing going on. From the photos I've seen of the guy's home I'd say he's not hurting for money, so the motive of very minor book sales appears pretty baseless. Ego? I don't know the guy, but from reading TToTC he doesn't come across as such. The whole endeavor carries with it significant legal liabilities which I assume he understood. A few people died and a whole lotta people spent tremendous time & money. If it was fake, Fenn's on the hook for fraud at least. Again, looking at photos of his home, I doubt he's gonna risk it all on a fake treasure hunt.
I suspect we will eventually learn who found it, after they've consulted a lawyer. The treasure itself is worth a lot but so is being the guy who found it, if you know how to market that. Personally, I hope the location is not revealed, and it gets turned into something akin to a geocache, without the geo. That is, place a capsule in the exact spot of the treasure with a log book. People can continue to "look for the treasure" and if they find it, put their name in the log book and hopefully continue to guard the secret.