>>34389796Colored carts were awesome, but I think the reason for their disappearance has more to do with how modern game systems worked than anything.
A Super Nintendo had the cart sticking up, out of it, with the title and sticker on full display. Nowadays, the media that holds the game data has changed. CDs aren't visible when they're in use, and while DS and 3DS games use cards, they're optimized to show themselves as little as possible while the game machine is running.
The original Gameboy had it so that you could look on the back of someone's handheld and know exactly what they're playing, as the sticker would be partially revealed, at least enough so that the title is visible.
I think a lot of this has to do with how hardware has changed over the years. People expect a sleek design that leaves the physical game close to invisible. If the game isn't visible, then there isn't much point in coloring the cart.
By the way, this isn't exclusive to Pokemon. some of the more memorable carts that had cool colors were Zelda 2 (gold), Maximum Carnage (red), and Donkey Kong 64 (yellow). There's probably more that I just didn't have. This one guy I knew in middle school had a WWF wrestling game with a black cart, but I forget what it is.
I hope this answered your question as to why they don't make them anymore, OP. And yes, I do miss them. I miss everything about older video games, though that might just be because I'm 28 and nostalgic.