But then wisdom is recognizing it's AP Physics, not common sense, that put a cow on the Moon. There may not be perfectly spherical cows in the real world, but

But then wisdom is recognizing it's AP Physics, not common sense, that put a cow on the Moon. There may not be perfectly spherical cows in the real world, but then real cows will also do X, to the extent their non-perfect-spheriness doesn't interfere with it. Theorists don't simplify for the sake of simplifying, they're trying to study specific components of the whole in isolation. Yes, it's important to not confuse a component for the whole thing, but then it's also important to know the most impactful components and how they behave.