I've wondered this myself for a long time as well. After the PSP came out, I really expected Microsoft to come out with some kind of handheld with the same color scheme as the (first) Xbox 360. I used to love playing games for GBA, but once everyone started making handheld consoles entirely 3D, it lost its charm for me. I figure, why play a 3D game on a handheld console when you can play it on a regular one? I know that it's about the portability, but I've never had that desire to play console-type games on the go. I liked handheld games specifically because they were different from console games, and once that distinction was gone I lost interest altogether.