Another theory is that the Satoshi persona was created by a group of individuals (cypherpunks) who were involved in the early Bitcoin community, including Hal Finney and Nick Szabo.
[1]: https://en.wikipedia.org/wiki/Satoshi_Nakamoto#Possible_iden...
The Bitcoin genesis block was created Jan 4, 2009 [2]
At that time there was about say 3 people in the world interested in these ideas. Make your judgement and consider the probabilities for P(Szabo = Satoshi) and P(Szabo != Satoshi).
I think if you read up on all the articles and convince yourself. In [3] Szabo said there is a lot similarities with Bitcoin and Bitgold, and he talked about the differences in interviews.
[1] http://unenumerated.blogspot.com/2005/12/bit-gold.html [2] https://blockexplorer.com/block/000000000019d6689c085ae16583... [3] https://www.youtube.com/watch?v=r_yUeuKu7L4