I believe the point the other person is making is that multinational tax compliance is inherently complicated. Moreover, it does not become simple and easy if a company just adopts a simple structure because the forces that drive that complexity are not a result of the complexity of a company's structure.

Think of it as tax engineering: companies build devices to avoid paying too much taxes. It's a thing, you'd do it too if you had enough money to justify the investment in such engineering :)

It sounds like what the other person is saying the primary motivation for this “engineering” is not to save money just because they could, it’s to avoid disputes and compliance risks as much possible (which incidentally results in them saving money). I can’t comment if that’s true or not, but I can easily imagine that this is the situation.