The ease with which he could prove he's Satoshi, and the fact he hasn't, and has been called out on an increasing number of re-edits, fakes, etc, could mean either;
He's not Satoshi
He is Satoshi but couldn't keep it to himself and doesn't want to prove ownership of the genesis block for financial/legal/privacy reasons
He is Satoshi but couldn't keep it to himself, but lost the keys ages ago as Bitcoin was only an experiment no one expected to take off
He's not Satoshi as an individual, but was involved with the original group that aliased themselves as Satoshi, just enough that he knows key information, dates, people, and so on, that he can continue to claim he is the sole Satoshi without it being too much of an internal lie, whilst at the same time not being able to prove or disprove it
He knows that it's Hal Finney and there's no one left alive to challenge him
I reckon it's either 1. with a good probability of 4. and 5.
This whole saga completely stinks and does nothing to help the image of blockchain advocates and the whole culture in general.
Yeah, that seems like a pretty concise outline of the most plausible scenarios.