Comment by ceejayoz
There aren't that many (11) levels.
https://en.wikipedia.org/wiki/Civil_service_of_the_People%27...
Functionally, the US mostly works the same way - people start in small local roles and move to county, state, and national levels over time. It's just not enforced as a hard rule, just a practical thing.
That makes more sense then. The US probably has around that number too and you’re right that we do mostly work up from the bottom. The most common method of avoiding the ladder is through military service but that’s basically a parallel ladder requiring very similar work.