Where do they go from there if they're already a professor from day one? Is there no promotion?
In the UK you won't get to be a professor until your forties, and many people never do.
In the UK you won't get to be a professor until your forties, and many people never do.
https://people.eecs.berkeley.edu/~bh/
who designed and then taught the introductory computer science course (CS 61A) for many years and is now retired.
Here professor is quite a distinguished title, and while it isn't legally protected, I've never seen it used for anyone except a very senior academic who has been formally appointed as a professor.