And he was able to stay silent for exactly 4 days. On December 17, 2010 a man named Peter Wuille created his bitcoin talk account. He is a member of the bitcoin development team and always has been. He arrived in the forum out of seemingly thin air and jumped right into the thick of things and has been there ever since.
That's not a very strong argument. 186 people joined Bitcointalk between December 10 and when Peter Wuille joined, and by your logic, any of those people could be satoshi. Furthermore, you are assuming that satoshi created an account
after he said goodbye. If he was planning on switching to a new account, it would also make sense that he created the new account
before his post, perhaps even months ahead of time.