That's not true. Yes amithlon does emulate a 680x0, but its not an amiga emulator as such and shares little in common with uae. Amithlon is more a way to get os3.x running on the metal on pc hardware as opposed to emulating an amiga.
Amithlon also lets a person run x86 AmigaOS3.x code under AmigaOS. You could compile 68k components to x86 code and run then in tandem with 68k.
While the OS itself makes only minor changes its not really accurate to say it didnt move forward and shares next to nothing in common with 68k "distros".
Perhaps you should learn about what it is youre typing before you type it?