I do not think Satoshi is a single person, but nobody knows that. What if they are groups of knowledgeable people. This is what people will think would have likely happened.
Most people still think that Satoshi wasn't a single person but no one can prove that because if we read posts of Satoshi's profile then we can understand that those posts were written by a single person, however still many people thing that one person can't have such level of smartness. I personally think that Satoshi might had a team where they worked together to make Bitcoin, but that's just my understanding, from the facts we can see that Satoshi was a single person not a team.
Whether Satoshi was a single individual or not, to me, the idea and progress of Bitcoin is nothing short of a masterpiece.
Although, the success of Bitcoin was built on failed technology of cryptography, POW, P2P networking, the result is so far amazing and flawless for the years it has existed that it even continues to evolve to meet modern demands.
What I would consider as Satoshi's greatest stroke of genius is his disappearing act. No trace, no sign, no proof of who he was. Hence, Bitcoin became completely decentralized and in the hands of those who run the nodes, mine the blocks and hold the keys.