> All an emulator is doing is changing the shape and flow of those commands.
Maybe if you're SIMH and you're emulating an old CPU that was connected asynchronously to like RS232 peripherals. But I think this statement understates the complexity of emulating something like a console.
Emulating a console or home computer, or even something like an old console's GPU, is HARD because you have to do these translations in a bug-for-bug compatible way, with strict timing constraints -- for the system's many components -- and you have to take into account the raster nature of CRT displays, which allowed for changing the display in significant ways between frames or scanlines.
There's a reason why emulation is these days usually only undertaken by some of the strangest most terminally online people, and it can take even them decades to get the details right. Of course, this engineer worked at Sony and probably had the benefit of being able to talk to the developers of the graphics chip he was emulating, but that's still a daunting task.