Your understanding is incorrect. Applications (games) written for older gaming consoles all had to ship some native code, and were even typically entirely nativ

Your understanding is incorrect. Applications (games) written for older gaming consoles all had to ship some native code, and were even typically entirely native code. These consoles were also typically not x86 or x86-64 based, so for a PC-targeting emulator to run applications written for these platforms, they do need to have recompiler or interpreter facilities. They also do not necessarily need to hook and replicate syscalls, provided the user provides a dump of the system software (they just run the system software and make it load the game - the original syscall codes are then ran). This extends even to the graphics hardware side once programmable shaders became a thing.