Here in Norway after the war we have had prime ministers who have been a teacher, farmer, road worker, electrician, medical doctor and ordained priest to name a few less common professions by American or Chinese standards. Interestingly before the 1900s when Norway had just two parties similar to the republicans and democrats all but one prime minister was a lawyer. As more parties got created and new groups of people represented in politics diversity also increased.
The problem for Norway may well be that while there is a whole lot of diversity up top, the bureaucratic structure has ossified.
It has gotten to be a decade now, but when last a right wing government was replaced with a (on paper) left wing one, the former finance minister was asked if he had faith in his replacement. His response was that while he could not comment on her abilities as a finance minister, he had full faith in her staff. This because it was the very same staff he had been working with.
A few years into the new government, another minister resigned. And afterwards she made a statement that there was a unstated agreement between the finance ministry, the oil and energy ministry, and the office of the prime minister about how the nation was to be run (the implied agreement was that oil and gas extraction was to be given priority above all else). And as a minister you needed to be very stubborn and thick skinned to break with that.
Note that this agreement was not between the ministers, but between the bureaucrats that worked there no matter who was nominally in charge.
