To be quite honest embassies are very different from what they once were. Once upon a time the American Ambassador to France was responsible for foreign relations and diplomatic expressions - the person chosen to hold the position was invested with a lot of power and responsibility.
These days national leaders can instantaneously communicate for most purposes (protected communications aren’t available for all nations so some sensitive conversations still need an in person component) and embassies serve more as a place for people abroad to interact with their government in emergency situations.
In most cases these embassies are just prestige appointments, all the diplomacy they do could effectively be done through representatives in New York (North Korea even has ambassadors in NYC) and there’s likely a reasonable way to consolidate citizen services (at least those that can’t be done by mail which most can).