I would be more than happy to demonstrate the superiority of anti-Mercantilist economics at any time.
I can't, because it's illegal.
It's doesn't have to be illegal to be poor, because being rich is just better. You have to outlaw being rich if you insist on folk being poor.
If Mercantilists (basically Communists) weren't afraid of being proven wrong, they wouldn't have to outlaw the alternative. Nobody has to outlaw jumping to the Moon, because it can't be done. You can't disprove gravity, because it's true. If trade were genuinely a bad idea, traders would suffer. At best, folk would constantly put up fences between themselves and traders.
In reality suppressing trade is astonishingly difficult, because trade just is the economy. Well over 99% of wealth is trade-based. Trade doesn't magically stop being cooperation when it happens across imaginary lines on a map. Trade just is the invisible hand. Cartel economics require extraordinary violence, which means it's extraordinarily expensive, which means it goes out of business if it has to pay for itself instead of stealing your pay.