My Shoei has a Pinlock visor which is a rather Heath Robinson method of reducing fogging.

Aeons ago (when I was probably about 13 years old, so like ages ago) my ski goggles had sealed unit double lenses to achieve the same thing without the Heath Robinson plastic add on that Pinlock is.

Why don't motorcycle visors use that same technology?

(Note - this arose because I rode over to Wellington today and had to change the Pinlock in my helmet this morning because it had become marked and scratched over the past 10 months of use to the point where it was negatively affecting my vision. Whilst Pinlock visors are not expensive, it seems wasteful)