Lady Liberty,
You point is one that I have thought a lot about and I genrally concur with your conclusion. Although I feel that he does have an organization eventhough it is not the only means of salvation.
Jesus was obviously Jah's channel but he recognized the possiblity that others not worshipping in the "normal" way could be on God's side. And your point indeed gives us a lot to think about.
My personal belief is that the sign of the son of man will be so dramatic that many will choose to align themselves with Jesus. This is a future event. If JWs are the true religion can imagine the surprise when many millions flock to Jesus based on his sign. These would not have had the time to serve in the "approved" way rather would come in at the last minute so to speak.