Increasing decrepitude

Today at lunch time I got my first pair of glasses ever. Not very strong ones, but they will supposedly make it easier for me to read. I had been promised them within 5–10 working days from prescription, but in fact they arrived in less than three.

What confuses me a bit is that the optics themselves seem not to cost anything, in spite of the necessity for grinding, surface treatment etc—the expensive bit is the frames, which basically are mass-produced pieces of plastic and/or metal. And of course, as such things go, frames that don't make you look like an idiot are expensive. I'm sure there is something strange and unwholesome behind this, but I'm not quite sure what yet.