What precisely measures the threshold that would have made the decline in investments a direct trigger and not just a correlation?
Without a sample representative of situations where an 18% drop systematically caused quotas, this claim lacks measurement.
Quota policies are often the result of long-term cultural and economic objectives, not just an annual fluctuation; think of the French regulation on cinema, which predates far beyond investment variations.
A direct causal link would require observable data showing that these quotas would not have been implemented if the decline had been less pronounced or absent.
Requiring a significant p-value in a political decision context is illusory, but the absence of solid quantitative evidence makes causality questionable.