I think the question the here is whether the laser is still reading the non playing disc, and if that will therefore decrease the laser life. This is a non trivial issue. Lasers can be replaced but it isn’t easy. Many threads here are about replacing lasers note difficulties due to discontinuation of player models, smaller companies no longer in Buisness, having to ship to Japan for repairs, etc.
I always assumed that when the disc stops playing, the laser stops reading. I really have no idea and now I will be more compulsive about turning off the player