Here is the core of the problem: a mathematical proof, no matter how solid, does not 'create' an equivalence in the real world without the appropriate conditions. It is the difference between the perfect plan of an architect and the reality of a building facing winds and earthquakes. Unforeseen exogenous shocks, such as a liquidity crisis or a sudden regulatory intervention by a national authority, modify the arc of history that theory anticipates. It is then necessary to consider the stable environment essential for this theoretical equivalence to be faithfully reflected in the financial markets, under penalty of a mismatch where actors run into walls. For example, sudden changes in import quotas can drastically alter the balances predicted by these sensitivities.