I think Satoshi Nakamoto is a community name, not a person. When you look at Bitcoin, you will see that it is impossible for a person to establish such a perfect financial system on his own. This group also made the first bitcoin mining and got rich and kept their hands off this business.
I think only one person discovered about bitcoin but he hide his identity using name satoshi nakamoto. Many asking who is satoshi nakamoto but no one can know who he is. May speculation but no one can guess.
And you can't say also that they are group discover bitcoin. Because as i read all and research sotoshi is only one person.