To sum it up: Yes you´re right (both of you in this case). To emulate such a complicated machinary bit by bit in sound or as a 3-D model (e.g. in a programm like CAD) this is really difficult and probably would need the understanding of an engineer.
BUT in Design and Art... the artist/designer plays with the perception of the viewer. (this is the main reason why I love art/design!!!) He has a deep understanding of the core elements and how a viewer will preceive them... as in "The Bull" from Pablo Picasso he plays exactly with that... he is restricting the Illustration of the bull to it´s core lines, and you still recognize it...
Same thing with this motor: The core element of the PERCEPTION of the motor sound (in motion) is the Pitch up/down... so this would be the first thing you try to nail... the complex timbre is just to add realism... and in audio especially in combination with picture/motion-picture you can lean yourself out of the window and don´t need to emulate ALL the sounds of the single parts of the motor... it is "just" art/design. The best design is the one, that only has the relevant things in it... (less is more)
And to make another analogy... let´s get back to the CAD 3-D model of the motor... if you only would have to make a representation of the motor without functionality you only sculpt the outside... the inside will be filled / or is even empty...
Form follows function --> so the question would be in which scenario the motor sound is needed: Is it a cheap game or is it for a complex animation for a 3-D model of the motorparts in motion.
Bye the way, I also love the fact, that Pablo Picaso felt the need to draw the "junk" of the bull at the simplified versions...
