Mastery Points should go down with time

With patch changes, the ever changing meta, reworks, etc. i believe your mastery with a champion should go down with time, people do get rusty when champions are unplayed for a while. Maybe introduce a change that makes you lose 100pts per day if you haven't played the champion in three months.

I've got a mastery 5 Fiora and Wukong that have been sitting there for over two years, i certainly can't play them today as well as i used to before.