Its tricky, though. There might be people who are doing a perfectly good job and kicking them arbitrarily might be suboptimal.

Then there is room for quite a lot of direct or indirect corruption. e.g. if you know you won't have a job in 4-8 years major corporations and other organizations offering you a cushy job if you do the "right things" might become quite a bit more appealing.

But yes, having a distinct class of career politicians has some significant downsides as well..

> The opposite is requiring people to ascend through the ranks (perhaps starting as low as a mayor of a town)

Might work fine or there might be a lot of gatekeeping if you just want to get on the first step since that will likely be controlled quite tightly by the established parties/cliques.