If it isn't Nick Szabo, it is somebody who has spent years ensuring all clues point to nobody but Nick Szabo, up to and including placing a Satoshi nakamoto statue in a rural Polish town where Nick Szabo's grandfather was born.

Let's just look at this logically: if you had written the 30+ papers building the ideas that eventually became bitcoin, actually were building bitcoin and months away from releasing, and then had all your work stolen without credit nor citation, you wouldn't be the world's biggest supporter of bitcoin. You would be mad that somebody stole your work and then spent years framing you for its creation.

The first usage of the word bitcoin was even on Nick Szabo's own blog, under a comment by the user Eddie. This leads to two outcomes: Eddie is Satoshi, or Nick's work wasn't stolen, bit gold is bitcoin and Nick is Satoshi.