Quite a few people believe it was a team instead of one person. I haven't research this far, but I trully believe that one gifted person alone, can actually manage to create a technological breakthrough that can change the lives of everyone. I believe that Satoshi is a single person that created everything with his own brilliant mind.

Patterns and technological advances that big corporations claim as their own, are usually build by one individual alone. His contract though, on every situation, claims that any breakthrough he achieves using company assets or data, is owned by the company. Scientists get paid a lot though for this reason. Although they miss the glory in most fields of science and technology this way and their name stays in the shadows.

I really hope Satoshi is alive and kicking and watching his child becoming what he always hoped for.
I read quite a few of his posts in bitcointalk and I only hold admiration for him.

If he is alive and decides to sell, he deserves the wealth. Kudos to him. Still it would have huge implications on price of Bitcoin.