>This is how most foreign services are run, with maybe the exception of China.

Absolutely not most. What country in Europe has a significant amount of ambassadors that are not career diplomats / government workers ?

In France, Germany, Switzerland you would either need to be a career diplomat/ foreign service worker or in rare cases you would be a career government employee assigned as diplomat to some specific country for some reason (i.e you were trade minister and become ambassador to your biggest trading partner).

The most "political" appointee ambassador in Europe I can think of is Mandelson but he is (as we found out) supremely connected to US power networks and he is still a lifetime politician/ government employee.