Maybe because they are cheap. The economic situation has deteriorated and people don't have much money to spend. Unfortunately, poverty has also penetrated the world of music, and when sound and mixing engineers wear these glasses, the situation for everyone else is deplorable.
The glasses thing maybe the related to the same moronic reasoning that is being used by almost 50% of the car driving public these days - turning lights on in the middle of the day for no reason at all. I can see it now. Dipshit driver: "But officer I didn't see them because they didn't have their lights on!!" Police Officer: "Well, excuse me sir, but it's the middle of the day, the sun is out, and visibility is completely clear" Police Officer: "Sir, exactly how did you get a driver's license?"
