Well, the n810 is the only one out of the three devices that is halfway usable for gaming controls, and not everyone has one. Another other problem is one of image, these are seen as more professional or only for internet browsing, whereas the GP2X is seen as a gaming platform. Another problem may be the default configuration of the OS. On the old Sharp Zarus SL-5500 I had, the default ROM was incapable of emulating GameBoy (orginal) at full speed, but flashing it to TKC allowed SNES emulation at an astonishing speed (nearly full speed on a 206MHz StrongArm). There is only a small amount of OS hacking going on, but that seems to be picking up.

Games/emulators will likely continue leaking in, and eventually, pending the updates don't keep breaking previous releases, the ITs will have a fair bit of emulators that run at decent speeds. The Pocket PC/Windows Mobile platform has a fairly professional image as well, but the shear backward compatibility (I have emulators intended for Palm-sized PC on my Windows Mobile 2003 PPC) puts it's library of emulators almost on par with the GP2X's library.