Yes, I know from baseball how these companies make money. I've been through something similar with baseball bats.
So my cousin has the first model, the Advance. Same as the one they sell now called Micro but different case if I read you right.
I just punched it into Wikipedia and found that there were two SP models. One was brighter. I don't know if this was advertised or not but if it was it would be another marketing ploy to get you to buy somemthing new, right?
This repackaging strategy sounds a little strange. It would be like redesigning a car's exterior but keeping the same engine, transmission, and brakes (and other underpinnings). So you get a 2006 model that looks brand new but it drives the same as the 2001.
So to get to the title of this post, I'm guessing the Game Boy will never die as long as people keep coming up with new case designs for the same thing. The Wikipedia article I looked up says that they won't kill it off.
I also saw the older Game Boys (which I remember some kids having in elementary school) went through the same thing, although the cases looked more alike there.
So to get this straight--there have been three models of Game Boy and all have had case-only redesigns accounting for nearly a dozen models. And the DS is a different system and is not part of the Game Boy line. (I'm concluding it's to the Game Boy what the Accord is to the Civic in Honda's line--something bigger, more powerful, and better). I'm sorry for making all my comparisons to cars, but it helps someone who's not as up on things in the video game world to understand!