It is easier in Finland that has similar existing institutions. The top person is usually a political appointee who is no longer active in politics - for instance a former PM. (being unicameral, there is no place to shuffle off the ex-PMs to.  

Tekes (Finnish Funding Agency for Technology and Innovation), for instance, has an oversight board made up more or less as I described earlier. Then there is strategic management, research management etc. It is cumbersome in some ways, but ensures that ideologies have less influence. Salaries are academic standard for the levels. Some business members at higher level are seconded by their companies.

But it is easier in Finland to get the best people because a) the differential in upper and lowers salaries is much narrower than in the US and b) a job with such an institution gives a valuable overview.

There is a certain amount of revolving door going on, but it is the sort of move that goes from macro to micro - ie a researcher or enabler for some new technology might leave the funding institution to join a project as a start-up, in order to guide it. As far as I know, this is actually encouraged. It's called seeding ideas and know-how.

You can't be me, I'm taken