This was suggested when proficiencies were initially introduced and was refused.
The main reason being that they were assigned to active elements such as fighting and skilling,
whereas armor is considered to be inactive in that it is a passive element of the game
If anything, it was suggested that continued use of a piece of armor would degrade it,
and that you would have to take it to something like an armory in order to repair it .. at a cost, of course.