Well clearly it is not impossible to recompile the program, perhaps by hand, into a different instruction set. Arguably this may be considered source to source

Well clearly it is not impossible to recompile the program, perhaps by hand, into a different instruction set. Arguably this may be considered source to source translation. Sure it is hard, and there's no program that will EVER be able to do it automatically I assume. But that does not leave out the possibility of hand translation, which may prove an effective means by super skilled programmers of the future.