'Those who can do, and then retire, and then pass the knowledge on after reaching 50yrs old.
those who can't do, lessen the standards in the long term.
Harsh?
Maybe, but 90% of the teachers I had aged under 50yrs old were a waste of time..
Education standards today to bear this argument out, I think.
(there are other factors to this, of course - but excellent teachers will mitigate a lot of these others factors out of the equation)
Yes, it depends how and why they got into the profession in some way plus, their willingness to go out and get practical life experience. Too many are career students.