If a state is not recognized by other states then it is isolated culturally, economically, educationally, and militarily (to name a few). There would be no trade for products requiring the state to be self-sufficient. Food crops would need to be grown in great quantities to feed the entire population. Manufacturing would be required to clothe, house, service everyone. This magnitude of isolation would prove detrimental to the populace.
Britania blocked the French coastlines to ensure that France cannot get allies and armies from it's colony so they could lose the war. The British navy controls French coasts that time of war
