Development of Creative Commons licenses

[Jen Gagne <jen AT beware-of-art.com>]

Hoping someone can confirm this interpretation so I don't have to pay  
a lawyer. ;) Here's a hypothetical scenario to explain my later  
question. Assume the players are "OriginalArtist," "MiddlemanGuy," and  
"Client."

1) OriginalArtist releases a photo under a "Attribution (by)" license,  
without a sharealike requirement.

2) MiddlemanGuy comes along and takes a copy, making note of the  
licensing terms. He makes a few token changes so it's considered a  
derivative image.

3) MiddlemanGuy then tells to his Client: "This derivative image is  
based on an original by OriginalArtist, who released it under a CC-by  
license. Now that I've attributed it in the manner OriginalArtist  
specified, I can sell or give you royalty-free full rights to use  
it... assuming you don't want to go get the original image, of course."

3) Client would have the option to go get the original image, but  
instead decides to take MiddlemanGuy up on his offer and get the  
derivative image.

4) End result: Client now can do whatever he or she chooses to do with  
the image under the terms of the agreement with MiddlemanGuy -- the  
original CC license no longer applies and OriginalArtist need not be  
attributed. (???)

... So, am I interpreting this correctly? Is this a natural result of  
how this license is designed, since it isn't sharealike and it's a  
step removed?

Thanks for your advice!