No one says that the actual source code (C or whatever) is "piped out". The machine instructions (in form of a binary) you have before decompiling is the code that is executed by the machine/emulator is copyrighted like any other data on the disc/cartridge. You are not writing the game yourself if you are decompiling it. And it's logically a derivative work. The fact that the resulting "instructions" is not the source code that developers wrote is as expected. It won't create it from thin air.

I don't understand what kind of mental gymnastics you need to do to think that you are doing something original here.