Comment by godelski

  > Everything is nice on paper

I think the reason this is true is mostly because how people do things "on paper". We can get much more accurate with "on paper" modeling, but the amount of work increases very fast. So it tends to be much easier to just calculate things as if they are spherical chickens in a vacuum and account for error than it is to calculate including things like geometry, drag, resistance, and all that other fun jazz (which you still will also need to account for error/uncertainty though this now can be smaller).

Which I think at the end of the day the important lesson is more how simple explanations can be good approximations that get us most of the way there but the details and nuances shouldn't be so easily dismissed. With this framing we can choose how we pick our battles. Is it cheaper/easier/faster to run a very accurate sim or cheaper/easier/faster to iterate in physical space?