It’s because they are not practical. They do not work inside cars, they transition super slow in winter, they are clear when you need sun glasses and dark when you need to see.

They work based on UV light. So they will not transition inside cars. They also will not transition in cold weather, so you’ll walk in snow with clear glasses and have dark ones for 5 minutes once you go inside.

Or that the CPU is not doing needles add servings.